嗯...

 

题目链接：https://www.luogu.org/problemnew/show/P3865

 

AC代码：

1 #include
      
        2 #include
       
         3 #include
        
          4  5 using namespace std; 6  7 int m, n, a[200005], st[200005][35]; 8  9 int main(){10     scanf("%d%d", &n, &m);11     for(int i = 1; i <= n; i++){12         scanf("%d", &a[i]);13         st[i][0] = a[i];14     }15     for(int j = 1; j <= log2(n); j++){16         for(int i = 1; i + (1 << j) - 1 <= n; i++){17             st[i][j] = max(st[i][j - 1], st[i + (1 << j - 1)][j - 1]);18         }19     }20     for(int i = 1; i <= m; i++){21         int l, r;22         scanf("%d%d", &l, &r);23         int k = log2(r - l + 1);24         printf("%d\n", max(st[l][k], st[r - (1 << k) + 1][k]));25     }26     return 0;27 }