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Author: black-shadows

Heaps and Maps/Activity Selection.cpp

@@ -0,0 +1,21 @@
+int Solution::solve(vector<int> &A, vector<int> &B) {
+    vector<pair<int,int> >ans;
+    priority_queue<pair<int,int>,vector<pair<int,int>>,greater<pair<int,int>>> q;
+    for(int i=0;i<A.size();i++)
+        q.push(make_pair(B[i],A[i]));
+    auto it = q.top();
+    int start = it.second;
+    int end = it.first;
+    q.pop();
+    ans.push_back(make_pair(start,end));
+    while(!q.empty()){
+        auto itr = q.top();
+        q.pop();
+        if(itr.second >= end){
+            start = itr.second;
+            end = itr.first;
+            ans.push_back(make_pair(start,end));
+        }
+    }
+    return (int)(ans.size());
+}

Heaps and Maps/Job Sequencing.cpp

@@ -0,0 +1,41 @@
+struct Job {
+   int dead;
+   int profit;
+};
+
+bool compare(const Job &a, const Job &b) {
+     return (a.profit > b.profit);
+}
+
+int solveit(vector<int> &A,vector<int> &B){
+    int n=A.size();
+    Job a[n];
+    for(int i=0; i<n; ++i){
+        a[i].dead=A[i];
+        a[i].profit=B[i];
+    }
+    sort(a,a+n,compare);
+    int result[n];
+    bool slot[n];
+    for (int i=0; i<n; i++)
+        slot[i] = false;
+    for(int i=0; i<n; i++) {
+       for (int j=min(n, a[i].dead)-1; j>=0; j--) {
+            if(slot[j]==false) {
+                result[j] = i;
+                slot[j] = true;
+                break;
+          }
+       }
+    }
+    int ans=0;
+    for(int i=0; i<n; i++)
+       if(slot[i])
+            ans+=a[result[i]].profit;
+
+    return ans;
+}
+
+int Solution::solve(vector<int> &A, vector<int> &B) {
+    return solveit(A,B);
+}

Heaps and Maps/Kth Smallest Element in a Sorted Matrix.cpp

@@ -0,0 +1,18 @@
+int Solution::solve(vector<vector<int> > &A, int B) {
+    int n=A.size();
+    int m=A[0].size();
+    priority_queue<int> q;
+    for(int i=0;i<n;i++){
+        for(int j=0;j<m;j++){
+            if(q.size()<B)
+                q.push(A[i][j]);
+            else{
+                if(A[i][j]<q.top()){
+                    q.pop();
+                    q.push(A[i][j]);
+                }
+            }
+        }
+    }
+    return q.top();
+}

Heaps and Maps/Task Scheduler.cpp

@@ -0,0 +1,14 @@
+int Solution::solve(string A, int B) {
+    unordered_map<char, int> record;
+    int max_freq = 0;
+    int max_tasks = 0;
+    for(auto a : A) {
+        record[a]++;
+        max_freq = max(max_freq, record[a]);
+    }
+    for (auto task : record)
+        if (task.second == max_freq)
+            max_tasks++;
+    int ans = (max_freq - 1) * (B+1) + max_tasks;
+    return ans > A.size() ? ans : A.size();
+}