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26 lines
839 B
C++
26 lines
839 B
C++
#define _CRT_SECURE_NO_WARNINGS
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#define _SILENCE_CXX17_C_HEADER_DEPRECATION_WARNING
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#include <algorithm>
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#include <cstdio>
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using namespace std;
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using ll = long long;
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const int N = 2e5 + 50;
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ll f[N][3], M[3], mod = 1e9 + 7;
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int main()
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{
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int n, l, r;
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scanf("%d%d%d", &n, &l, &r);
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f[0][0] = 1;
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M[0] = (r / 3) - ((l - 1) / 3);
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M[1] = ((r + 1) / 3) - ((l - 1 + 1) / 3);
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M[2] = ((r + 2) / 3) - ((l - 1 + 2) / 3);
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for (int i = 1; i <= n; i++)
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{
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f[i][0] = (f[i - 1][0] * M[0] % mod + f[i - 1][1] * M[2] % mod + f[i - 1][2] * M[1] % mod) % mod;
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f[i][1] = (f[i - 1][1] * M[0] % mod + f[i - 1][2] * M[2] % mod + f[i - 1][0] * M[1] % mod) % mod;
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f[i][2] = (f[i - 1][2] * M[0] % mod + f[i - 1][0] * M[2] % mod + f[i - 1][1] * M[1] % mod) % mod;
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}
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printf("%lld", f[n][0]);
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return 0;
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}
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