HDU 1166(敌兵布阵)

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区间求和，以前线段树写的，用树状数组写了一下，还是树状数组好用啊。。T_T

而且树状数组的时间好像比线段树要快，编程复杂度更低。。

/*********************** author:crazy_石头* Pro:HDU 1166* algorithm:树状数组求区间和* Time:31ms* Judge Status:Accepted***********************/#include <iostream>#include <cstring>#include <cstdlib>#include <cstdio>#include <queue>#include <vector>using namespace std;#define rep(i,h,n) for(int i=(h);i<=(n);i++)#define ms(a,b) memset((a),(b),sizeof(a))#define eps 1e-6#define INF 1<<29#define LL __int64const int maxn=50000+5;const int maxm=200+10;int C[maxn],a[maxn];//树状数组为C数组，相当于一个前缀和数组；int n;inline int lowbit(int x){    return x&-x;}inline void update(int x,int y){    while(x<=n)    {        C[x]+=y;        x+=lowbit(x);    }}inline int getsum(int x){    int res=0;    while(x>0)    {        res+=C[x];        x-=lowbit(x);    }    return res;}int main(){    int test,t=1,num;    char str[maxn];    scanf("%d",&test);    while(test--)    {        printf("Case %d:\n",t++);        scanf("%d",&n);        ms(C,0);        rep(i,1,n)        {            scanf("%d",&num);            update(i,num);        }        scanf("%s",str);        while(str[0]!='E')        {            int x,y;            scanf("%d%d",&x,&y);            if(str[0]=='A')                update(x,y);            else if(str[0]=='S')                update(x,-y);            else                printf("%d\n",getsum(y)-getsum(x-1));            scanf("%s",str);        }    }    return 0;}