14 lines
367 B
C++
14 lines
367 B
C++
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#include <bits/stdc++.h>
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using namespace std;
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int main() {
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//cin读入优化
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std::ios::sync_with_stdio(false);
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float n;
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cin >> n;
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if (n >= 0 && n < 5) printf("%.3f", 0 - n + 2.5);
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else if (n >= 5 && n < 10) printf("%.3f", 2 - 1.5 * (n - 3) * (n - 3));
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else if (n >= 10 && n < 20) printf("%.3f", n / 2 - 1.5);
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return 0;
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}
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