17 lines
383 B
C++
17 lines
383 B
C++
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#include <bits/stdc++.h>
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using namespace std;
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//给出等差数列的前两项，分别是a1,a2,问第n项是多少
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int x, y, n;
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int main() {
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cin >> x >> y >> n;
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int z = y - x;
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if (n == 1) cout << x << endl;
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if (n == 2) cout << y << endl;
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if (n >= 3) {
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for (int i = 3; i <= n; i++)y += z;
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cout << x << endl;
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}
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return 0;
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}
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