【HDOJ】1754 I Hate It

线段树。

 #include <iostream>
 #include <cstdio>
 #include <cstring>
 using namespace std;

 #define mymax(a, b) (a>b) ? a:b

 const int maxn = ;

 int nums[maxn<<];

 void PushUP(int rt) {
     nums[rt] = mymax(nums[rt<<], nums[rt<<|]);
 }

 void build(int l, int r, int rt) {
     if (l == r) {
         scanf("%d", &nums[rt]);
         return ;
     }
     int mid = (l+r)>>;
     build(l, mid, rt<<);
     build(mid+, r, rt<<|);
     PushUP(rt);
 }

 int query(int ll, int rr, int l, int r, int rt) {
     if (ll <= l && rr>= r)
         return nums[rt];
     int mid = (l+r)>>;
     int max = -, tmp = -;
     if (ll <= mid) {
         max = query(ll, rr, l, mid, rt<<);
     }
     if (rr > mid) {
         tmp = query(ll, rr, mid+, r, rt<<|);
         if (tmp > max)
             max = tmp;
     }
     return max;
 }

 void update(int des, int val, int l, int r, int rt) {
     if (l == r) {
         nums[rt] = val;
         return ;
     }
     int mid = (l+r)>>;
     if (des <= mid)
         update(des, val, l, mid, rt<<);
     else
         update(des, val, mid+, r, rt<<|);
     PushUP(rt);
 }

 int main() {
     int n, m;
     int i, j;
     char cmd[];

     while (scanf("%d %d", &n, &m) != EOF) {
         build(, n, );
         while (m--) {
             scanf("%*c%s %d %d", cmd, &i, &j);
             if (cmd[] == 'Q')
                 printf("%d\n", query(i,j,,n,));
             else
                 update(i,j,,n,);
         }
     }

     return ;
 }