题意:给定一个坐标系,每个点有一个值,值可以改变,求任意矩形所围的值得大小。
#include <iostream> using namespace std; #define S 1025 int c[S][S], n; int lowbit ( int x ) { return x & ( -x ); } void modify ( int x, int y, int v ) { int i, j; for ( i = x; i <= n; i += lowbit(i) ) { for ( j = y; j <= n; j += lowbit(j) ) c[i][j] += v; } } int sum ( int x, int y ) { int i, j, sum = 0; for ( i = x; i > 0; i -= lowbit(i) ) { for ( j = y; j > 0; j -= lowbit(j) ) sum += c[i][j]; } return sum; } int getSum ( int x1, int y1, int x2, int y2 ) { return sum(x2,y2) - sum(x2,y1-1) - sum(x1-1,y2) + sum(x1-1,y1-1); } int main() { int oper, x1, y1, x2, y2, v; scanf("%d%d",&oper,&n); memset(c,0,sizeof(c)); while ( scanf("%d",&oper) && oper != 3 ) { if ( oper == 1 ) { scanf("%d%d%d",&x1,&y1,&v); modify ( x1+1, y1+1, v ); } else if ( oper == 2 ) { scanf("%d%d%d%d",&x1,&y1,&x2,&y2); printf("%d\n", getSum ( x1+1, y1+1, x2+1, y2+1 ) ); } } return 0; }