P1208 [USACO1.3]混合牛奶 Mixing Milk
阿新 • • 發佈:2022-03-09
// Problem: P1208 [USACO1.3]混合牛奶 Mixing Milk // Contest: Luogu // URL: https://www.luogu.com.cn/problem/P1208 // Memory Limit: 125 MB // Time Limit: 1000 ms // User: Pannnn #include <bits/stdc++.h> using namespace std; template<class T> void debugVector(const T &a) { cout << "[ "; for (size_t i = 0; i < a.size(); ++i) { cout << a[i] << (i == a.size() - 1 ? " " : ", "); } cout << "]" << endl; } template<class T> void debugMatrix2(const T &a) { for (size_t i = 0; i < a.size(); ++i) { debugVector(a[i]); } } template<class T> using matrix2 = vector<vector<T>>; template<class T> vector<vector<T>> getMatrix2(size_t n, size_t m, T init = T()) { return vector<vector<T>>(n, vector<T>(m, init)); } template<class T> using matrix3 = vector<vector<vector<T>>>; template<class T> vector<vector<vector<T>>> getMatrix3(size_t x, size_t y, size_t z, T init = T()) { return vector<vector<vector<T>>>(x, vector<vector<T>>(y, vector<T>(z, init))); } vector<int> genBigInteger(string a) { vector<int> res; for (int i = a.size() - 1; i >= 0; --i) { res.push_back(a[i] - '0'); } return res; } void printBigInteger(vector<int> a) { for (size_t i = a.size() - 1; i >= 0; --i) { cout << a[i]; } } vector<int> addBigInteger(vector<int> a, vector<int> b) { vector<int> res; int pre = 0; for (size_t i = 0; i < a.size() || i < b.size() || pre; ++i) { if (i < a.size()) pre += a[i]; if (i < b.size()) pre += b[i]; res.push_back(pre % 10); pre /= 10; } return res; } int main() { ios::sync_with_stdio(false); cin.tie(0); int n, m; cin >> n >> m; vector<pair<int, int>> info(m); for (int i = 0; i < m; ++i) { cin >> info[i].first >> info[i].second; } sort(info.begin(), info.end()); int res = 0; for (int i = 0; i < m && n > 0; ++i) { if (info[i].second >= n) { res += info[i].first * n; } else { res += info[i].first * info[i].second; } n -= info[i].second; } cout << res << endl; return 0; }