47 lines
798 B
C++
47 lines
798 B
C++
#include <bits/stdc++.h>
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using namespace std;
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const int N = 2e5 + 10;
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const int MOD = 1e9 + 7;
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int n, a, b, c;
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int f[N];
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int ans;
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int main() {
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#ifndef ONLINE_JUDGE
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freopen("20240301.in", "r", stdin);
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#endif
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/**
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例1：
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1 1 1 1
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答案：1
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例2：
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114 51 4 1
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答案：176
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例3：
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114514 191 9 810
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答案：384178446
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*/
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// 从大向小推
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cin >> n >> a >> b >> c;
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f[n] = 1;
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for (int i = n; i > c; i--) {
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if (i - a >= 0)
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f[i - a] = (f[i - a] + f[i]) % MOD;
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else
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f[0] = (f[i] + f[0]) % MOD;
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if (i - b >= 0)
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f[i - b] = (f[i - b] + f[i]) % MOD;
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else
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f[0] = (f[0] + f[i]) % MOD;
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}
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for (int i = 0; i <= c; i++)
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ans = (ans + f[i]) % MOD;
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printf("%d\n", ans);
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return 0;
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} |