Color the ball (树状数组实现差分)

链接

用树状数组实现差分，对左端点做add(L, value)，对右端点做add(R, -value).最后查询的时候是每一个位置的前缀和.

参考代码：

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

using i64 = long long;

constexpr int M = 1e5 + 10;

int tree[M], N;

void add(int x, int value) {
    for (int i = x; i <= N; i += (i & (-i))) {
        tree[i] += value;
    }
}//单点修改

int query(int x) {
    int ans = 0;
    for (int i = x; i >= 1; i -= (i & (-i))) {
        ans += tree[i];
    }
    return ans;
}//查询前缀和

template 
inline void read(T &f) {
    f = 0; T fu = 1; char c = getchar();
    while (c < '0' || c > '9') { if (c == '-') { fu = -1; } c = getchar(); }
    while (c >= '0' && c <= '9') { f = (f << 3) + (f << 1) + (c & 15); c = getchar(); }
    f *= fu;
}

int main() {
    while (1) {
        read(N);
        if (N == 0) {
            break;
        }
        std::memset(tree, 0, sizeof tree);
        for (int i = 1; i <= N; i++) {
            int x, y;
            read(x), read(y);
            add(x, 1), add(y + 1, -1);
        }
        for (int i = 1; i <= N; i++) {
            printf("%d%s", query(i), (i == N ? "\n" : " "));
        }
    }
    return 0;
}