CF EDU 130, finished a and b

codeforces/educational_rounds/130/b.cpp

@@ -0,0 +1,38 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int main(){
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+
+    int n, q;
+    cin >> n >> q;
+
+    vector<int> p(n);
+    for(int i = 0; i < n; ++i){
+        cin >> p[i];
+    }
+
+    sort(p.begin(), p.end());
+
+    vector<uint64_t> bottom_sums(n+1);
+
+    uint64_t sum = 0;
+    for(int i = 0; i <= n; ++i){
+        bottom_sums[i] = sum;
+        sum += p[i];
+    }
+
+    for(int i = 0; i < q; ++i){
+        int x, y;
+        cin >> x >> y;
+
+        uint64_t ans = bottom_sums[n - x + y] - bottom_sums[n - x];
+        cout << ans << '\n';
+    }
+
+    cout << flush;
+
+    return 0;
+}