22 lines
495 B
C++
22 lines
495 B
C++
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#include <bits/stdc++.h>
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using namespace std;
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int w, n;
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const int N = 30010;
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int a[N];
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//双指针
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int h = 1, t = n, cnt;
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int main() {
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cin >> w >> n;
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for (int i = 1; i <= n; i++)cin >> a[i];
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sort(a + 1, a + 1 + n);
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//双指针，太聪明的办法了
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while (h <= t)
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if (a[t] + a[h] > w) cnt++, t--; //装不下的话,a[t]独立成组
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else cnt++, t--, h++;//能装下的话，a[t]+a[h]为一组
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cout << cnt << endl;
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return 0;
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}
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