树状数组模版

1.一维树状数组

// 获得2^k

public static int lowbit(int i) {

return i & -i;

}

//修改结点

public static void add(int i, int value) {

while (i <= MAX) {

c[i] += value;

i += lowbit(i);

}

}

//求和

public static int getSum(int i) {

int sum = 0;

while (i > 0) {

sum += c[i];

i -= lowbit(i);

}

return sum;

}

2.二维树状数组

public static int lowbit(int i) {

return i & -i;

}

public static void change(int i, int j, int value) {

while (i <= n) {

int temp = j;

while (temp <= n) {

matrix[i][temp] += value;

temp += lowbit(temp);

}

i += lowbit(i);

}

}

public static int getSum(int i, int j) {

int sum = 0;

while (i > 0) {

int tmp = j;

while (tmp > 0) {

sum += matrix[i][tmp];

tmp -= lowbit(tmp);

}

i -= lowbit(i);

}

return sum;

}