32 lines
866 B
C++
32 lines
866 B
C++
#include <bits/stdc++.h>
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using namespace std;
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#define l second
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#define r first
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typedef pair<int, int> PII;
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const int INF = 0x3f3f3f3f;
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const int N = 1e5 + 10;
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int n;
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PII a[N];
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/*
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由于pair会自动以first升序排列所以用pair就不用自己重载小于运算符，至于first和second的先后关系其实没什么意义。
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只要在输入/存储时交换一下x,y顺序即可，如果觉得容易混可以直接定义l为second,r为first就不会混了，同理以左端点排序的题一样
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*/
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int res, ed = -INF;
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int main() {
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cin >> n;
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for (int i = 0; i < n; i++) {
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int x, y;
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cin >> x >> y;
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a[i] = {y, x};
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}
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sort(a, a + n);
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for (int i = 0; i < n; i++) {
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if (a[i].l > ed) {
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res++;
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ed = a[i].r;
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}
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}
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cout << res << endl;
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return 0;
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}
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