很简单的模拟，我是用的优先队列。不多说，上代码(这是bjfuoj的，hdu的要稍改一下)：
/* * Author : ben */ #include <cstdio> #include <cstdlib> #include <cstring> #include <cmath> #include <ctime> #include <iostream> #include <algorithm> #include <queue> #include <set> #include <map> #include <stack> #include <string> #include <vector> #include <deque> #include <list> #include <functional> #include <numeric> #include <cctype> using namespace std; typedef struct Stone { int p, d; Stone(int pp, int dd) { p = pp; d = dd; } } Stone; inline bool operator<(const Stone &s1, const Stone &s2) { if (s1.p != s2.p) { return s1.p > s2.p; } return s1.d > s2.d; } //输入非负整数，用法int a = get_int(); int get_int() { int res = 0, ch; while (!((ch = getchar()) >= '0' && ch <= '9')) { if (ch == EOF) return -1; } res = ch - '0'; while ((ch = getchar()) >= '0' && ch <= '9') res = res * 10 + (ch - '0'); return res; } int main() { int n, p, d, ans; bool flag; while ((n = get_int()) > 0) { priority_queue<Stone> pq; for (int i = 0; i < n; i++) { p = get_int(); d = get_int(); pq.push(Stone(p, d)); } ans = 0; flag = true; while (!pq.empty()) { Stone s = pq.top(); ans = s.p; pq.pop(); if (flag) { s.p += s.d; pq.push(s); } flag = !flag; } printf("%d ", ans); } return 0; }