洛谷 P1047 [NOIP2005 普及组] 校门外的树

Posted on Edited on In 
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#include <iostream>
using namespace std;
int l, m, u, v, tree[10001] = {0}, cnt = 0;
int main() {
    cin >> l >> m;
    for (int i = 0; i < m; ++i) {
        cin >> u >> v;
        while (u <= v)
            tree[u++] = 1;
    }
    for (int i = 0; i <= l; ++i)
        if (tree[i] == 0)
            ++cnt;
    cout << cnt << endl;
    return 0;
}
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#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int l, m, cnt = 0;
int main() {
    cin >> l >> m;
    vector<vector<int>> v(m, vector<int>(2));
    for (int i = 0; i < m; ++i)
        cin >> v[i][0] >> v[i][1];
    sort(begin(v), end(v));
    int i = 0, j = 0;
    while (j < m) {
        if (i <= v[j][1]) {
            i = max(i, v[j][0]);
            cnt += v[j][1] - i + 1;
            i = v[j][1] + 1;
        }
        ++j;
    }
    cout << l + 1 - cnt << endl;
    return 0;
}