Solution #2438 - Neha Amin - 12/08/2025

Arrays & Strings/#2438 - Range Product Queries of Powers- Medium/productQueries.java

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+import java.util.*;
+
+class Solution {
+    private final int mod = (int)1e9 + 7;
+
+    public int[] productQueries(int n, int[][] queries) {
+        List<Integer> p2 = new ArrayList<>();
+        List<Integer> res = new ArrayList<>();
+        int i = 0, k = 0;
+
+        while (n > 0) {
+            if ((n & 1) == 1) {
+                p2.add(i);
+                if (k > 0) {
+                    p2.set(k, p2.get(k) + p2.get(k - 1)); // prefix sum of exponents
+                }
+                k++;
+            }
+            n >>= 1;
+            i++;
+        }
+
+        for (int[] q : queries) {
+            int p = p2.get(q[1]) - (q[0] > 0 ? p2.get(q[0] - 1) : 0);
+            res.add(fastPow(2, p));
+        }
+
+        // Convert List<Integer> to int[]
+        return res.stream().mapToInt(Integer::intValue).toArray();
+    }
+
+    private int fastPow(int base, int exp) {
+        long result = 1;
+        long b = base;
+        while (exp > 0) {
+            if ((exp & 1) == 1) {
+                result = (result * b) % mod;
+            }
+            b = (b * b) % mod;
+            exp >>= 1;
+        }
+        return (int) result;
+    }
+}

Arrays & Strings/#2438 - Range Product Queries of Powers- Medium/productQueries.py

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+class Solution:
+    MOD = 10**9 + 7
+
+    def productQueries(self, n: int, queries: list[list[int]]) -> list[int]:
+        p2 = []
+        i = k = 0
+
+        while n:
+            if n & 1:
+                p2.append(i)
+                if k > 0:
+                    p2[k] += p2[k - 1]  # prefix sum of exponents
+                k += 1
+            n >>= 1
+            i += 1
+
+        res = []
+        for q in queries:
+            p = p2[q[1]] - (p2[q[0] - 1] if q[0] > 0 else 0)
+            res.append(self.fastPow(2, p))
+        return res
+
+    def fastPow(self, base: int, exp: int) -> int:
+        result = 1
+        while exp:
+            if exp & 1:
+                result = (result * base) % self.MOD
+            base = (base * base) % self.MOD
+            exp >>= 1
+        return result