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:\n", ++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\n", ask(a, b, 1, n, 1));}}}return 0; }
iOS面试题目)
