Create sum-of-matrix-after-queries.cpp

Author: kamyu104

C++/sum-of-matrix-after-queries.cpp

@@ -0,0 +1,22 @@
+// Time:  O(n + q)
+// Space: O(n)
+
+// hash table
+class Solution {
+public:
+    long long matrixSumQueries(int n, vector<vector<int>>& queries) {
+        vector<vector<bool>> lookup(2, vector<bool>(n));
+        vector<int> cnt(2);
+        int64_t result = 0;
+        for (int i = size(queries) - 1; i >= 0; --i) {
+            const int t = queries[i][0], idx = queries[i][1], v = queries[i][2];
+            if (lookup[t][idx]) {
+                continue;
+            }
+            lookup[t][idx] = true;
+            ++cnt[t];
+            result += v * (n - cnt[t ^ 1]);
+        }
+        return result;
+    }
+};