P2947 [USACO09MAR]向右看齐Look Up
题目描述
Farmer John’s N (1 <= N <= 100,000) cows, conveniently numbered 1..N, are once again standing in a row. Cow i has height H_i (1 <= H_i <= 1,000,000).
Each cow is looking to her left toward those with higher index numbers. We say that cow i ‘looks up’ to cow j if i < j and H_i < H_j. For each cow i, FJ would like to know the index of the first cow in line looked up to by cow i.
Note: about 50% of the test data will have N <= 1,000.
约翰的N(1≤N≤10^5)头奶牛站成一排,奶牛i的身高是Hi(l≤Hi≤1,000,000).现在,每只奶牛都在向右看齐.对于奶牛i,如果奶牛j满足i
#include <cstdio>
#define N 100005
using namespace std;
struct stack
{
int val,num;
}s[N];
int size,n,a[N],b[N];
int main()
{
scanf("%d", &n);
for (int i = 1; i <= n; i++)
scanf("%d", &a[i]);
for (int i = n; i >= 1; i--)
{
while (size > 0 && a[i] >= s[size].val) size--;
b[i] = s[size].num;
s[++size].num = i;
s[size].val = a[i];
}
for (int i = 1; i <= n; i++)
printf("%d\n", b[i]);
}