【luogu P2251 质量检测】 题解

也是一道ST表的板子题，很裸的RMQ问题，只需要在查询区间时处理一下下就好啦~

#include <cstdio>
#include <algorithm>
using namespace std;
const int maxn = 1000000 + 10;
int st[maxn][21], a[maxn], ans[maxn];
int n, m, i, j, left, right;
int main()
{
    scanf("%d%d", &n, &m);
    for(i = 1; i <= n; i++)
    {
        scanf("%d", &a[i]);
        st[i][0] = a[i];
    }
    
    for(j = 1; (1<<j) <= n; j++)
        for(i = 1; i <= n-(1<<j)+1; i++)
        st[i][j] = min(st[i][j-1],st[i+(1<<(j-1))][j-1]);
    
    right = m;
    for(i = 1; i <= n-m+1; i++)
    {
        j = 0;
        left = i;
        while((1<<(j+1)) <= (right-left+1)) j++;
        ans[i] = min(st[left][j],st[right-(1<<j)+1][j]);
        right++;
    }
    
    for(i = 1; i <= n-m+1; i++)
    printf("%d\n",ans[i]);
    return 0;
}