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Author: DhruvPasricha

Practice/.cph/.Playing_with_digits.cpp_af9218bd9a1f01ac9c7fe321eb0081ed.prob

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+{"name":"Playing with digits","group":"HackerEarth","url":"https://www.hackerearth.com/problem/algorithm/playing-with-digits-4e25844f/","interactive":false,"memoryLimit":256,"timeLimit":1000,"tests":[{"input":"5 86 4\n","output":"7\n","id":1618372966642}],"testType":"single","input":{"type":"stdin"},"output":{"type":"stdout"},"languages":{"java":{"mainClass":"Main","taskClass":"PlayingWithDigits"}},"batch":{"id":"2bfe465b-a194-49fb-b80b-5a0510776f00","size":1},"srcPath":"c:\\Users\\Dhruv\\myGithub\\Competitive-Programming\\Practice\\Playing_with_digits.cpp"}

Practice/Playing_with_digits.cpp

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+
+//------------------------------------------------------------------------------
+// #include <iostream>
+// #include <vector>
+#include <bits/stdc++.h>
+// #include <cmath>
+// #include <algorithm>
+// #include <unordered_map>
+// #include <map>
+// #include <set>
+// #include <unordered_set>
+//------------------------------------------------------------------------------
+using namespace std;
+//------------------------------------------------------------------------------
+#define FastIO ios_base::sync_with_stdio(false), cin.tie(NULL), cout.tie(NULL);
+#define v(Type) vector<Type>
+#define w(T)  \
+    int T;    \
+    cin >> T; \
+    while (T--)
+#define int long long int
+#define mod 1000000007ll
+#define endl "\n"
+//------------------------------------------------------------------------------
+// Any fucntion can be called using Math.function_name();
+//------------------------------------------------------------------------------
+class Math
+{
+public:
+    //Returns gcd of two numbers
+    int gcd(int a, int b)
+    {
+        return (a % b == 0) ? b : gcd(b, a % b);
+    }
+
+    //Returns lcm of two numbers
+    int lcm(int a, int b)
+    {
+        return a * (b / gcd(a, b));
+    }
+
+    // Returns flag array isPrime
+    // isPrime[i] = true (if i is Prime)
+    // isPrime[i] = false (if i is not Prime)
+    vector<bool> *seiveOfEratosthenes(const int N)
+    {
+        vector<bool> *isPrime = new vector<bool>(N + 1, true);
+        (*isPrime)[0] = (*isPrime)[1] = false;
+        for (int i = 2; i * i <= N; ++i)
+            if ((*isPrime)[i])
+                for (int j = i * i; j <= N; j += i)
+                    (*isPrime)[j] = false;
+
+        return isPrime;
+    }
+
+    //Returns (x ^ n)
+    int pow(const int &x, int n)
+    {
+        if (n == 0)
+            return 1;
+        int h = pow(x, n / 2);
+        return (n & 1) ? h * h * x : h * h;
+    }
+
+    //Returns (x ^ n) % M
+    int pow(const int &x, int n, const int &M)
+    {
+        if (n == 0)
+            return 1;
+        int h = pow(x, n / 2) % M;
+        return (n & 1) ? (h * h * x) % M : (h * h) % M;
+    }
+
+    //Returns all Primes <= N
+    vector<int> *primesUptoN(const int N)
+    {
+        vector<bool> *isPrime = seiveOfEratosthenes(N);
+        vector<int> *Primes = new vector<int>;
+        if (2 <= N)
+            (*Primes).push_back(2);
+        for (int i = 3; i <= N; i += 2)
+            if ((*isPrime)[i])
+                (*Primes).push_back(i);
+        return Primes;
+    }
+
+} Math;
+//------------------------------------------------------------------------------
+
+v(bool) isPrime = *Math.seiveOfEratosthenes(100);
+
+static int dp[11][2][100][4001];
+int solve(string &s, int pos, bool tight, int sum, int rem, int &k)
+{
+    if (pos == s.length())
+        return isPrime[sum] and rem == 0;
+
+    if (dp[pos][tight][sum][rem] != -1)
+        return dp[pos][tight][sum][rem];
+
+    int ub = (tight) ? s[pos] - '0' : 9;
+    int ans = 0;
+    for (int i = 0; i <= ub; i++)
+        ans += solve(s, pos + 1, tight and (i == ub), sum + i, (rem * 10 + i) % k, k);
+
+    return dp[pos][tight][sum][rem] = ans;
+}
+int f(string &s, int k)
+{
+    for (int pos = 0; pos < s.length(); pos++)
+        for (int tight = 0; tight <= 1; tight++)
+            for (int sum = 0; sum <= 9 * s.length(); sum++)
+                for (int rem = 0; rem < k; rem++)
+                    dp[pos][tight][sum][rem] = -1;
+    int ans = solve(s, 0, 1, 0, 0, k);
+    return ans;
+}
+
+bool check(int x)
+{
+    int sum = 0;
+    while (x)
+    {
+        sum += x % 10;
+        x /= 10;
+    }
+    return isPrime[sum];
+}
+
+void solve()
+{
+    int a, b;
+    cin >> a >> b;
+
+    a--;
+    string r = to_string(b);
+    string l = to_string(a);
+
+    int k;
+    cin >> k;
+
+    int ans = 0;
+    if (k <= 4000)
+        ans = f(r, k) - f(l, k);
+    else
+    {
+        a++;
+        int s = (a % k == 0) ? a : k + a - a % k;
+        // cout << s << endl;
+        while (s <= b)
+        {
+            ans += check(s);
+            s += k;
+        }
+    }
+    cout << ans << endl;
+}
+
+//------------------------------------------------------------------------------
+int32_t main()
+{
+    FastIO;
+
+    // w(T)
+    solve();
+
+    return 0;
+}
+//------------------------------------------------------------------------------