poj 2559

#include <iostream>#include <cstdio>using namespace std;const int N = 100005;struct Elem{int height;int count;};Elem stack[N];int top;int main(){int height, n;long long ans, tot, tmp;while (scanf("%d", &n) != EOF && n){top = 0;ans = 0;for (int i = 0; i < n; ++i){scanf("%d", &height);tmp = 0;while (top > 0 && stack[top - 1].height >= height){tot = stack[top - 1].height * (stack[top - 1].count + tmp);if (tot > ans) ans = tot;tmp += stack[top - 1].count;--top;}stack[top].height = height;stack[top].count = 1 + tmp;++top;}int tmp = 0;while (top > 0){tot = stack[top - 1].height * (stack[top - 1].count + tmp);if (tot > ans) ans = tot;tmp += stack[top - 1].count;--top;}printf("%lld\n", ans);}return 0;}