C - Zero Path

https://codeforces.com/contest/1695/submission/161141066

Codeforces/1695/C/C.cpp

@@ -0,0 +1,56 @@
+#pragma GCC optimize("O3,unroll-loops")
+#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
+
+#include <iostream>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int t;
+
+    cin >> t;
+
+    while (t--) {
+        int n, m;
+
+        cin >> n >> m;
+
+        std::vector<std::vector<int>>
+            g(n, std::vector<int>(m)),
+            f1(n, std::vector<int>(m)),
+            f2(n, std::vector<int>(m));
+
+        for (auto& e : g) {
+            for (auto& v : e) {
+                cin >> v;
+            }
+        }
+
+        f1[0][0] = f2[0][0] = g[0][0];
+
+        for (int i = 1; i < m; i++) {
+            f1[0][i] = f2[0][i] = f1[0][i - 1] + g[0][i];
+        }
+
+        for (int i = 1; i < n; i++) {
+            f1[i][0] = f2[i][0] = f1[i - 1][0] + g[i][0];
+        }
+
+        for (int i = 1; i < n; i++) {
+            for (int j = 1; j < m; j++) {
+                f1[i][j] = std::max(f1[i - 1][j], f1[i][j - 1]) + g[i][j];
+                f2[i][j] = std::min(f2[i - 1][j], f2[i][j - 1]) + g[i][j];
+            }
+        }
+
+        cout << (f1[n - 1][m - 1] % 2 == 0 && f1[n - 1][m - 1] >= 0 && f2[n - 1][m - 1] <= 0 ? "YES" : "NO") << endl;
+    }
+
+    return 0;
+}