89 lines
1.7 KiB
C++
89 lines
1.7 KiB
C++
#include <bits/stdc++.h>
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#define int long long
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using namespace std;
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int a, b;
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int dp[35][35];
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int getlen(int num)
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{
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if (num < 10)
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return 1;
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int cnt = 0;
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while (num)
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{
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num /= 10;
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cnt++;
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}
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return cnt;
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}
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int calc(int x)
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{
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if (x <= 0)
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return 0;
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vector<int> digit;
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while (x)
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{
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digit.push_back(x % 10);
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x /= 10;
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}
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int len = digit.size();
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int res = 0;
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for (int i = 1; i < len; ++i)
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{
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for (int j = 1; j <= 9; ++j)
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{
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res += dp[i][j];
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}
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}
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for (int i = len - 1; i >= 0; --i)
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{
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int cur = digit[i];
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int start = (i == len - 1) ? 1 : 0;
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for (int j = start; j < cur; ++j)
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{
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if (i == len - 1 || abs(j - digit[i + 1]) >= 2)
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{
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if (i == 0)
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{
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++res;
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}
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else
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{
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res += dp[i + 1][j];
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}
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}
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}
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if (i != len - 1 && abs(cur - digit[i + 1]) < 2)
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{
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break;
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}
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if (i == 0)
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{
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++res;
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}
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}
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return res;
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}
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signed main()
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{
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scanf("%lld%lld", &a, &b);
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int _b = getlen(b);
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for (int i = 0; i <= 9; ++i)
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{
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dp[1][i] = 1;
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}
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for (int i = 2; i <= _b; ++i)
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{
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for (int j = 0; j <= 9; ++j)
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{
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for (int k = 0; k <= 9; ++k)
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{
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if (abs(j - k) < 2)
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continue;
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dp[i][j] += dp[i - 1][k];
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}
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}
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}
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printf("%lld\n", calc(b) - calc(a - 1));
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return 0;
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} |