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coderxiangcoderxiang
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changchun regional 2012
1 parent fcbd633 commit a88140f

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6 files changed

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‎ZJU/ZJU_2588_bridge.cpp

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/*
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* Finding the bridge of undirected graph (with multiple edges between two nodes)
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*/
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#include <cstdio>
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#include <algorithm>
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#include <vector>
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#include <cstring>
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using namespace std;
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const int N = 10010;
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const int M = 300000;
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struct enode {
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int to, nxt, id;
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enode () {};
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enode (int tt, int nn, int dd): to (tt), nxt (nn), id(dd) {};
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}e[M];
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int eb[N], en;
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int bic_vis[N], bic_low[N], n, m, stamp, Nbridge;
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bool isBridge[M];
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void adde (int x, int y, int id) {
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e[en] = enode (y, eb[x], id);
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eb[x] = en++;
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e[en] = enode (x, eb[y], id);
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eb[y] = en++;
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}
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void DFS (int x, int pre) {
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int i, j;
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bic_vis[x] = bic_low[x] = ++ stamp;
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for (int ee = eb[x]; ee != -1; ee = e[ee].nxt) if (pre == -1 || e[ee].id != e[pre].id) {
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j = e[ee].to;
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if (!bic_vis[j]) {
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DFS (j, ee);
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bic_low[x] = min (bic_low[x], bic_low[j]);
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if (bic_low[j] > bic_vis[x])
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isBridge[e[ee].id] = true, Nbridge ++;
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}
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else bic_low[x] = min (bic_low[x], bic_vis[j]);
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}
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}
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vector <pair<int,int> >edge;
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int main ()
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{
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int i, j, k, T;
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scanf ("%d", &T);
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for (int ca = 1; ca <= T; ca ++) {
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memset (eb, -1, sizeof (eb));
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en = 0;
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memset (bic_vis, 0, sizeof (bic_vis));
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memset (bic_low, 0, sizeof (bic_low));
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memset (isBridge, false, sizeof (isBridge));
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stamp = Nbridge = 0;
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scanf ("%d%d", &n, &m);
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for (k = 1; k <= m; k++) {
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scanf ("%d%d", &i, &j);
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edge.push_back (make_pair (i, j));
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adde (i, j, k);
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}
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DFS (1, -1);
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printf ("%d\n", Nbridge);
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for (i = 0, j = 0; i < m; i++) {
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if (isBridge[i+1]){ j++;
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printf ("%d%c", i + 1, j == Nbridge ? '\n': ' ');
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}
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}
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if (ca != T) printf ("\n");
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}
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return 0;
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}

‎ZJU/ZJU_3318.cpp

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/*
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* ZJU 3318: DP: forward is better than backward
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* 3/19/2012, 10:47 pm
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*/
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#include <iostream>
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#include <vector>
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#include <queue>
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#include <string>
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#include <list>
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#include <set>
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#include <map>
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#include <sstream>
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#include <algorithm>
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#include <cstring>
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#include <cmath>
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#include <ctime>
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#include <cstdio>
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using namespace std;
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typedef long long ll;
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typedef pair<int,int> PII;
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typedef vector<int> VI;
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typedef vector<string> VS;
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#define pb push_back
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#define mp make_pair
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#define ff first
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#define ss second
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#define sz(v) (int)v.size()
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#define clr(x, v) memset(x, v, sizeof(x))
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#define rep(i, l, u) for(int i = (l); i < (u); i++)
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#define repv(i, v) for(i = 0; i < (int)v.size(); i++)
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#define repi(it, c) for(typeof(c.begin()) it = c.begin(); it != c.end(); ++it)
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const int N = 35;
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const int DA = 35;
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const int inf = 1000;
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bool g[DA][N][N];
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bool ad[N][N];
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int n;
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int BFS (int sc, int ds)
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{
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int i, j;
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int q[N], head, tail;
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bool st[N] = {false};
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int dis[N]; for (i = 1; i <= n; i++) dis[i] = inf;
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q[head = tail = 1] = sc; st[sc] = true; dis[sc] = 0;
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if (sc == ds) return 0;
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while (head <= tail) {
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i = q[head++];
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for (j = 1; j <= n; j++) if (ad[i][j] && !st[j]) {
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st[j] = true; dis[j] = dis[i] + 1;
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if ((q[++tail] = j) == ds) return dis[ds];
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}
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}
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return dis[ds];
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}
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int main ()
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{
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int i, j, k, m, T, Nrd, sc, ds;
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int d[DA];
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for (scanf ("%d", &T); T; T--) {
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clr (g, false);
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scanf ("%d%d%d%d", &n, &m, &sc, &ds);
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for (k = 1; k <= m; k++) {
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for (scanf ("%d", &Nrd); Nrd; Nrd--) {
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scanf ("%d%d", &i, &j);
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g[k][i][j] = g[k][j][i] = true;
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}
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}
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for (i = 1; i <= m; i++) d[i] = inf*inf;
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for (i = 0; i < m; i++) {
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clr (ad, true);
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for (j = i + 1; j <= m; j++) {
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rep (ii, 1, n + 1)
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rep (jj, 1, n + 1)
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ad[ii][jj] = ad[ii][jj] && g[j][ii][jj];
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k = BFS (sc, ds);
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if (i == 0)
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d[j] = k * j;
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else d[j] = min (d[j], d[i] + k * (j-i) + 1);
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}
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}
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printf ("%d\n", d[m]);
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}
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return 0;
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}
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‎ZJU/ZJU_3331.cpp

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#include <cstdio>
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#include <cstring>
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#include <algorithm>
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using namespace std;
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const int N = 110;
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int d[N][N<<1];
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int main () {
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int i, j, k, ta, tb, T, n;
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for (scanf ("%d", &T); T; T--) {
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scanf ("%d", &n);
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memset (d, 0x3f, sizeof (d));
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d[0][100] = 0;
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for (i = 0; i < n; i++) {
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scanf ("%d%d", &ta, &tb);
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for (j = 0; j <= 200; j++) {
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if ( j >= 100 ) {
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d[i+1][ta+100] = min (d[i+1][ta+100], d[i][j] + ta);
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d[i+1][j - tb] = min (d[i+1][j - tb], (j - 100 >= tb ? d[i][j]: d[i][j] + 100 + tb - j));
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}
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else {
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d[i + 1][100 - tb] = min (d[i + 1][100 - tb], d[i][j] + tb);
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d[i + 1][j + ta] = min (d[i + 1][j + ta], j + ta >= 100 ? d[i][j] + ta + j - 100 : d[i][j]);
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}
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}
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}
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int ans = 1000000010;
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for (j = 0; j <= 200; j++) ans = min (ans, d[n][j]);
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printf ("%d\n", ans);
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}
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return 0;
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}
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‎ZJU/ZJU_3656.cpp

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#include <cstdio>
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#include <cstring>
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#include <algorithm>
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using namespace std;
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const int N = 1010;
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int b[N][N];
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bool ad[N][N];
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int scc, id[N];
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int n, nn;
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int low[N], vis[N];
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int stk[N], top;
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bool in_stack[N];
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int stamp;
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int nt[N];
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void DFS (int u) {
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vis[u] = low[u] = ++stamp;
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in_stack [stk[++top] = u] = true;
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for (int i = 0; i < nn; ++i) {
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if (!ad[u][i]) continue;
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if (!vis[i]) {
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DFS (i);
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low[u] = min (low[i], low[u]);
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}
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else if (in_stack [i])
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low[u] = min (low[u], vis[i]);
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}
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if (low[u] != vis[u]) return;
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scc++;
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int i;
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do {
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i = stk[top--];
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id[i] = scc;
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in_stack[i] = false;
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}while (i != u);
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}
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void calc_scc () {
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memset (vis, 0, sizeof (vis));
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memset (in_stack, false, sizeof (in_stack));
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scc = stamp = top = 0;
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for (int i = 0; i < nn; ++i)
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if (!vis[i]) DFS (i);
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}
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inline void add_term (int x, int y) {
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ad[nt[x]][y] = true;
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ad[nt[y]][x] = true;
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}
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bool chk (int bt) {
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memset (ad, false, sizeof (ad));
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nn = 1000;
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for (int i = 0; i < n; ++i)
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for (int j = i + 1; j < n; ++j) {
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if (i % 2 == 1 && j % 2 == 1) {
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if (b[i][j] & (1<<bt)) // i or j
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add_term (i, j);
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else {// ni and nj
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add_term (nt[i], nt[i]);
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add_term (nt[j], nt[j]);
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}
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}
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else if (i % 2 == 0 && j % 2 == 0) {
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if (b[i][j] & (1<<bt)) { // i and j
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add_term (i, i);
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add_term (j, j);
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}
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else { // nt (i) or nt (j)
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add_term (nt[i], nt[j]);
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}
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}
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else {
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if (b[i][j] & (1<<bt)) { // i ^ j = (i or j) and ( nt(i) or nt(j) )
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add_term (i, j);
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add_term (nt[i], nt[j]);
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}
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else { // (i or nt (j)) and (nt (i) or j)
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add_term (i, nt[j]);
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add_term (nt[i], j);
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}
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}
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}
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calc_scc ();
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for (int i = 0; i < n; ++i)
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if (id[i] == id[nt[i]])
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return false;
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// printf ("bit %d\n", bt);
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// for (int i = 0; i < n; ++i)
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// printf ("%d %d\n", id[i], id[nt[i]]);
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return true;
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}
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int main () {
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int i, j, k;
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for (i = 0; i < 1000; ++i)
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nt[i] = i >= 500 ? i - 500 : i + 500;
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//freopen ("in", "r", stdin);
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while (scanf ("%d", &n) == 1) {
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bool flag = true;
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for (i = 0; i < n; ++i)
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for (j = 0; j < n; ++j) {
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scanf ("%d", &b[i][j]);
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if (i == j && b[i][j] != 0 || i > j && b[i][j] != b[j][i]) {
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flag = false;
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}
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}
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for (int bt = 0; flag && bt < 31; ++bt) {
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if (!chk (bt)) {
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flag = false;
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break;
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}
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}
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printf ("%s\n", flag ? "YES" : "NO");
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}
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return 0;
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}

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