NYOJ 116 士兵殺敵（二）【線段樹 單點更新】

標籤：線段樹   單點更新   

題意：題意很清楚；

策略；如題。

這道題就是簡單的線段樹應用，據說還可以用樹狀數組來做，等我學了之後在說吧。

代碼：

#include<stdio.h>#include<string.h>#define LC l, m, rt<<1#define RC m+1, r, rt<<1|1#define LL long long#define MAXN 1000000LL sum[MAXN<<2];void PushUp(int rt){sum[rt] = sum[rt<<1]+sum[rt<<1|1];}void creat(int l, int r, int rt){if(l == r){scanf("%lld", &sum[rt]);return;}int m = (l+r)>>1;creat(LC);creat(RC);PushUp(rt);}void update(int p, int num, int l, int r, int rt){if(l == r){sum[rt] += (LL)num;return;}int m = (l+r)>>1;if(p <= m) update(p, num, LC);else update(p, num, RC);PushUp(rt);}LL query(int ll, int rr, int l, int r, int rt){if(ll <= l&&r<= rr){return sum[rt];}LL res = 0;int m = (l+r)>>1;if(ll <= m) res += query(ll, rr, LC);if(rr > m) res += query(ll, rr, RC);return res;}int main(){int n, m;scanf("%d%d", &n, &m);creat(1, n, 1);char s[10];int a, b;while(m -- ){scanf("%s", s);if(s[0] == 'Q'){scanf("%d%d", &a, &b);printf("%lld\n", query(a, b, 1, n, 1));}else{scanf("%d%d", &a, &b);update(a, b, 1, n, 1);}}return 0;}

題目連結：http://acm.nyist.net/JudgeOnline/problem.php?pid=116