题意：二维树状数组，更改值的时候有一点不一样，
是将a[x][y]设置为一个值，所以add的时候要将它和以前的值作差一下
1 #include<iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include <cmath> 5 #include<stack> 6 #include<vector> 7 #include<map> 8 #include<set> 9 #include<queue> 10 #include<algorithm> 11 using namespace std; 12 13 typedef long long LL; 14 const int INF = (1<<30)-1; 15 const int mod=1000000007; 16 const int maxn=5005; 17 18 int a[maxn][maxn]; 19 int c[maxn][maxn];//树状数组 20 int n; 21 22 int lowbit(int x){ return x & (-x);} 23 24 int sum(int x,int y){ 25 int ret=0; 26 int y1; 27 while(x > 0){ 28 y1 = y; 29 while(y1 > 0){ 30 ret += c[x][y1];y1-=lowbit(y1); 31 } 32 x-=lowbit(x); 33 } 34 return ret; 35 } 36 37 void add(int x,int y,int d){ 38 int y1; 39 while(x < maxn){ 40 y1 = y; 41 while (y1 < maxn){ 42 c[x][y1]+=d; y1+=lowbit(y1); 43 } 44 x+=lowbit(x); 45 } 46 } 47 48 int main(){ 49 int T; 50 scanf("%d",&T); 51 while(T--){ 52 memset(c,0,sizeof(c)); 53 memset(a,0,sizeof(a)); 54 scanf("%d",&n); 55 char s[15]; 56 while(scanf("%s",s)!=EOF){ 57 if(s[0] == 'E') break; 58 if(s[1]=='E'){ 59 int x,y,num; 60 scanf("%d %d %d",&x,&y,&num);x++;y++; 61 int tmp = num - a[x][y]; 62 a[x][y] = num; 63 add(x,y,tmp); 64 } 65 if(s[1]=='U'){ 66 int x,y,xx,yy; 67 int ans=0; 68 scanf("%d %d %d %d",&x,&y,&xx,&yy); 69 x++;y++;xx++;yy++; 70 ans = sum(xx,yy) - sum(x-1,yy) - sum(xx,y-1) + sum(x-1,y-1); 71 printf("%d ",ans); 72 } 73 } 74 } 75 return 0; 76 }