29 lines
647 B
C++
29 lines
647 B
C++
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#include <bits/stdc++.h>
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using namespace std;
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typedef pair<int, int> PII;
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#define x first
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#define y second
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const int N = 5010;
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PII a[N]; // 南岸和北岸的一对友好城市的坐标
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int f[N], fl; // 数组模拟栈
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int n; // n组友好城市
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int res;
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int main() {
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cin >> n;
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for (int i = 1; i <= n; i++) cin >> a[i].x >> a[i].y;
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sort(a + 1, a + 1 + n);
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f[++fl] = a[1].y;
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for (int i = 2; i <= n; i++) {
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if (a[i].y > f[fl])
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f[++fl] = a[i].y;
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else
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*lower_bound(f + 1, f + 1 + fl, a[i].y) = a[i].y;
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}
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printf("%d\n", fl);
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return 0;
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}
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