入门线段树，单点更新。写了几遍，都是学着notonlysuccess写的。
#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[444444]; void up(int rt) { sum[rt] = 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); } 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 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 += ask(L, R, lson); if (R>mid) ans += ask(L, R, rson); return ans; } char str[100]; int main() { int Icase; int n; scanf("%d", &Icase); int tt = 0; while (Icase--){ printf("Case %d: ", ++tt); scanf("%d", &n); build(1, n, 1); for (;;){ int a; int b; scanf("%s", str); if (str[0] == 'E') break; scanf("%d%d", &a, &b); if (str[0] == 'A'){ update(a, b, 1, n, 1); } if (str[0] == 'S'){ update(a, -b, 1, n, 1); } if (str[0] == 'Q'){ printf("%d ", ask(a, b, 1, n, 1)); } } } return 0; }