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ZJU Monthly March 2013 (1)
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‎ZJU/3686.cpp

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// ZOJ Monthly March 2013
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// DFS sequence + segment tree
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#include <cstdio>
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#include <algorithm>
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#include <cstring>
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#include <vector>
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using namespace std;
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const int N = 100011;
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vector<int> g[N];
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int n;
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int L[N<<2], R[N<<2], C[N<<2];
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bool f[N<<2];
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int be[N], en[N], stp;
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void DFS (int u, int pre) {
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int i, j, k;
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be[u] = ++stp;
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k = g[u].size ();
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for (i = 0; i < k; ++i){
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j = g[u][i];
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if (j != pre) DFS (j, u);
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}
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en[u] = stp;
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}
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void build (int u, int x, int y) {
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L[u] = x; R[u] = y; f[u] = false; C[u] = 0;
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if (x < y) {
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int mid = (x + y) / 2;
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build (u * 2, x, mid);
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build (u * 2 + 1, mid + 1, y);
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}
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}
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void push_down (int u);
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void ins (int u, int x, int y) {
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if (x <= L[u] && y >= R[u]) {
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f[u] = !f[u];
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C[u] = R[u] - L[u] + 1 - C[u];
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return;
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}
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int mid = (L[u] + R[u]) / 2;
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push_down (u);
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if (x <= mid)
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ins (u * 2, x, y);
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if (y > mid)
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ins (u * 2 + 1, x, y);
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C[u] = C[u*2] + C[u*2+1];
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}
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void push_down (int u) {
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if (f[u]) {
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f[u] = false;
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ins (u * 2, L[u], R[u]);
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ins (u * 2 + 1, L[u], R[u]);
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}
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}
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int q (int u, int x, int y) {
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if (x <= L[u] && y >= R[u])
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return C[u];
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push_down (u);
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int mid = (L[u] + R[u]) / 2;
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int ans = 0;
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if (x <= mid)
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ans += q (u * 2, x, y);
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if (y > mid)
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ans += q (u * 2 + 1, x, y);
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return ans;
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}
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int main () {
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int i, j, k, m;
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char ch;
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while (scanf ("%d%d", &n, &m) == 2) {
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for (i = 1; i <= n; ++i) g[i].clear ();
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for (i = 2; i <= n; ++i) {
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scanf ("%d", &j);
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g[j].push_back (i);
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g[i].push_back (j);
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}
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stp = 0;
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DFS (1, 0);
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build (1, 1, stp);
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for (; m; --m) {
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getchar ();
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scanf ("%c %d", &ch, &i);
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if (ch == 'o')
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ins (1, be[i], en[i]);
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else
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printf ("%d\n", q(1, be[i], en[i]));
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}
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printf ("\n");
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}
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return 0;
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}

‎ZJU/3689.cpp

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#include <cstdio>
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#include <algorithm>
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#include <cstring>
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#include <vector>
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using namespace std;
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const int T = 10011;
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const int N = 3011;
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int d[T], n;
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struct node {
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int s, t;
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bool operator < (const node &e) const {
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return e.s * t < s * e.t;
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}
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}a[N];
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int main () {
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int i, j, k, n, m;
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while (scanf ("%d%d", &n, &m) == 2) {
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for (i = 1; i <= n; ++i)
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scanf ("%d%d", &a[i].t, &a[i].s);
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sort (a + 1, a + n + 1);
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memset (d, 0, sizeof (d));
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for (i = 1; i <= n; ++i) {
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for (j = 0; j + a[i].t <= m; ++j)
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d[j] = max (d[j], d[j + a[i].t] + (j + a[i].t) * a[i].s);
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}
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printf ("%d\n", *max_element (d, d + m + 1));
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}
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return 0;
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}
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‎ZJU/3690.cpp

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// ZOJ Monthy March 2013.
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// DP & Matrix Power
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#include <cstdio>
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#include <algorithm>
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#include <cstring>
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using namespace std;
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const int md = 1000000007;
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// a[i] = (k - 1) * a[i-1] + k * b[i-1]
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// b[i] = (n - k) * (a[i - 1] + b[i - 1])
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// (a, b) = [k - 1 k; n-k n-k] * (a, b)
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long long mem[2][2];
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void mat_mul (long long a[][2], long long b[][2], long long c[][2]) {
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int i, j, k;
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memset (mem, 0, sizeof (mem));
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for (i = 0; i < 2; ++i)
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for (j = 0; j < 2; ++j) {
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mem[i][j] = 0;
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for (k = 0; k < 2; ++k)
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mem[i][j] = (mem[i][j] + b[i][k] * c[k][j]) % md;
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}
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memcpy (a, mem, sizeof(mem));
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}
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void mat_pow (long long b[][2], int e) {
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long long ans[][2] = {{1,0}, {0,1}};
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while (e) {
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if (e & 1)
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mat_mul (ans, ans, b);
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mat_mul (b, b, b);
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e /= 2;
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}
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memcpy (b, ans, 4 * sizeof(long long));
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}
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int main () {
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int i, j, k;
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int m, n;
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while (scanf ("%d%d%d", &m, &n, &k) == 3) {
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long long a[][2] = {{k-1,k},{n-k,n-k}};
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mat_pow (a, m);
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printf ("%Ld\n", (a[0][1] + a[1][1]) % md);
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}
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return 0;
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}

‎ZJU/3691.cpp

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// ZOJ Monthy March 2013.
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// Network Flow
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#include <cstdio>
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#include <cstring>
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#include <algorithm>
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#include <cmath>
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using namespace std;
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const int N = 511;
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const int M = 60000;
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const int INF = 10000010;
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struct enode{
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int to, f, nxt;
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enode() : to(0), f(0), nxt(0) {}
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enode(int to1, int f1, int nxt1): to(to1), f(f1), nxt(nxt1) {}
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}e[M];
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int eb[N], en;
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int curA[N], pre[N];
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int d[N], gap[N];
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int totN;
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inline void adde(int x, int y, int c)
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{
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e[en] = enode(y, c, eb[x]); eb[x] = en++;
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e[en] = enode(x, 0, eb[y]); eb[y] = en++;
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}
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int DDflow(int ss, int tt)
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{
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int i, j, k, ff, ee;
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int ans = 0;
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memset(d, 0, sizeof(d));
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memset(gap, 0, sizeof(gap));
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gap[0] = totN;
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i = ss; ff = INF;
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while(d[ss] < totN){
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for(ee = curA[i]; ee != -1; ee = curA[i] = e[ee].nxt){
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j = e[ee].to;
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if(e[ee].f > 0 && d[i] == d[j] + 1){
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ff = min(ff, e[ee].f); pre[j] = ee;
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i = j; break;
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}
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} // Stop searching admissible arc
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if(ee == -1){ // If admissible arc NOT found
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int md = totN;
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for(ee = eb[i]; ee != -1; ee = e[ee].nxt) if(e[ee].f > 0)
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md = min(d[e[ee].to] + 1, md);
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if(--gap[d[i]] == 0) return ans; // Gap Heuristic
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gap[d[i] = md]++; curA[i] = eb[i]; // Relabel and Reset Current Arc
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if(i != ss) i = e[pre[i]^1].to; // Retreat
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} // Relabel and Retreat finished, keep searching for admissible arc
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if(i == tt){ // If admissible path found, then augment
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j = tt; ans += ff;
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while(j != ss){ e[pre[j]].f -= ff; e[pre[j]^1].f += ff; j = e[pre[j]^1].to;}
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i = ss; ff = INF;
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} // Augment successfully
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}
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return ans;
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}
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int X[N], Y[N], Z[N], F[N], L[N];
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int dis[N*N], dmat[N][N];
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int n;
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bool chk (int d, int anony) {
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int i, j;
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memset(eb, -1, sizeof(eb)); // DO NOT forget
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en = 0;
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int src = 0, des = 1, tot = 0;
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for(i = 1; i <= n; i++) {
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adde (src, i, F[i]); tot += F[i];
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adde (i, i + n, L[i]);
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if (dmat[i][1] <= d)
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adde (i + n, des, INF);
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for (j = 1; j <= n; ++j)
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if (i != j && dmat[i][j] <= d)
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adde (i + n, j, INF);
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}
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totN = 2 * n + 1;
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memcpy(curA, eb, sizeof(eb)); // DO NOT forget
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return DDflow (src, des) != tot;
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}
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int main()
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{
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int i, j;
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while (scanf ("%d", &n) == 1) {
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for (i = 1; i <= n; ++i)
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scanf ("%d%d%d%d%d", &X[i], &Y[i], &Z[i], &F[i], &L[i]);
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int cnt = 0;
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for (i = 1; i <= n; ++i)
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for (j = i + 1; j <= n; ++j)
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dis[cnt++] = dmat[i][j] = dmat[j][i] = (X[i] - X[j]) * (X[i] - X[j]) + (Y[i] - Y[j]) * (Y[i] - Y[j]) + (Z[i] - Z[j]) * (Z[i] - Z[j]);
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sort (dis, dis + cnt);
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cnt = unique (dis, dis + cnt) - dis;
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i = lower_bound(dis, dis+cnt, 0, chk) - dis;
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if (i == cnt) puts("-1");
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else printf ("%.7lf\n", sqrt(dis[i]));
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}
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return 0;
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}
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