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32 lines
522 B
32 lines
522 B
#include <bits/stdc++.h>
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using namespace std;
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/*
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f(1)=1
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f(2)=2
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f(3)=4
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f(4)=7
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*/
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//递归解法
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int dp(int n) {
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if (n == 1) return 1;
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if (n == 2) return 2;
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if (n == 3) return 4;
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return dp(n - 1) + dp(n - 2) + dp(n - 3);
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}
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const int N = 110;
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int f[N];
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int main() {
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int n;
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scanf("%d", &n);
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printf("%d\n", dp(n));
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f[1] = 1, f[2] = 3, f[3] = 4;
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for (int i = 4; i <= n; i++) f[i] = f[i - 1] + f[i - 2] + f[i - 3];
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printf("%d\n", f[n]);
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return 0;
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}
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