Create choose-numbers-from-two-arrays-in-range.cpp

Author: kamyu104

C++/choose-numbers-from-two-arrays-in-range.cpp

@@ -0,0 +1,25 @@
+// Time:  O(n^2 * v), v is max(max(nums1), max(nums2))
+// Space: O(n * v)
+
+// dp
+class Solution {
+public:
+    int countSubranges(vector<int>& nums1, vector<int>& nums2) {
+        static const int MOD = 1e9 + 7;
+        
+        int result = 0;
+        unordered_map<int, int> dp;
+        for (int i = 0; i < size(nums1); ++i) {
+            unordered_map<int, int> new_dp;
+            ++new_dp[nums1[i]];
+            ++new_dp[-nums2[i]];
+            for (const auto& [v, c] : dp) {
+                new_dp[v + nums1[i]] = (new_dp[v + nums1[i]] + c) % MOD;
+                new_dp[v - nums2[i]] = (new_dp[v - nums2[i]] + c) % MOD;
+            }
+            dp = move(new_dp);
+            result = (result + dp[0]) % MOD;
+        }
+        return result;
+    }
+};