18 lines
386 B
C++
18 lines
386 B
C++
#include<bits/stdc++.h>
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using namespace std;
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typedef long long ll;
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int main() {
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ll a, b, s = 0, n;
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cin >> a >> b;
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for (ll y = a; y <= b; y++) {
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n = y;//不能改变循环变量的原值，所以要找“替身”
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while (n != 0) {
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if (n % 10 == 2) s++;
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n /= 10;
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}
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}
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cout << s << endl;
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return 0;
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} |