标签:blog io for sp 2014 on log html amp
维护一个单调递减的栈 每次家进栈首的牛必定可以被其他栈里面的牛看到
#include <cstdio> #include <cstring> using namespace std; const int maxn = 80010; typedef unsigned long long LL; int a[maxn], s[maxn]; int main() { int n; scanf("%d", &n); for(int i = 1; i <= n; i++) scanf("%d", &a[i]); int top = 0; LL ans = 0; for(int i = 1; i <= n; i++) { while(top && a[i] >= a[s[top]]) top--; ans += top; s[++top] = i; } printf("%llu\n", ans); return 0; }
标签:blog io for sp 2014 on log html amp
原文地址:http://blog.csdn.net/u011686226/article/details/40116219