和上一题差不多，单点更新，求和，求最值，求乘积之类的，都可以照着搞。
#include <cstdio> #include <cstring> #include <algorithm> #include <climits> #include <string> #include <iostream> #include <map> #include <cstdlib> #include <list> #include <set> #include <queue> #include <stack> using namespace std; #define lson l,mid,rt<<1 #define rson mid+1,r,rt<<1|1 int sum[888888]; void up(int rt) { sum[rt] = max(sum[rt << 1], sum[rt << 1 | 1]); } void build(int l, int r, int rt) { if (l == r){ scanf("%d", &sum[rt]); return; } int mid = (l + r) >> 1; build(lson); build(rson); up(rt); } int ask(int L, int R, int l, int r, int rt) { if (L <= l&&r <= R)return sum[rt]; int mid = (l + r) >> 1; int ans = 0; if (L <= mid) ans = max(ans, ask(L, R, lson)); if (R>mid) ans = max(ans, ask(L, R, rson)); return ans; } void update(int key, int add, int l, int r, int rt) { if (l == r){ sum[rt] = add; return; } int mid = (l + r) >> 1; if (key <= mid) update(key, add, lson); else update(key, add, rson); up(rt); } int main() { int n, m; int a, b; char str[100]; while (scanf("%d%d", &n, &m) != EOF){ build(1, n, 1); for (int i = 0; i<m; i++){ scanf("%s", str); scanf("%d%d", &a, &b); if (str[0] == 'U'){ update(a, b, 1, n, 1); } else printf("%d ", ask(a, b, 1, n, 1)); } } return 0; }