C++ 代码实现：计算马路上剩余的树木数量

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main() {
    int L, M;
    cin >> L >> M;
    
    vector<int> trees(L+1, 1); // 初始化马路上的树
    
    for (int i = 0; i < M; i++) {
        int start, end;
        cin >> start >> end;
        
        // 将区域内的树移走
        for (int j = start; j <= end; j++) {
            trees[j] = 0;
        }
    }
    
    // 统计剩余的树的数目
    int remaining = count(trees.begin(), trees.end(), 1);
    
    cout << remaining << endl;
    
    return 0;
}