B - The least round way

https://codeforces.com/contest/2/submission/181030934

Codeforces/2/B/B.cpp

@@ -0,0 +1,117 @@
+#include <iostream>
+#include <algorithm>
+#include <string>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1005;
+
+int n, zx, zy, a[N][N], f[N][N][2];
+bool g[N][N][2], flag;
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n;
+
+    for (int i = 1; i <= n; i++) {
+        for (int j = 1, x; j <= n; j++) {
+            cin >> x;
+
+            if (x == 0) {
+                flag = true;
+                zx = i, zy = j;
+
+                continue;
+            }
+
+            while (x % 2 == 0) {
+                x /= 2;
+                f[i][j][0]++;
+            }
+
+            while (x % 5 == 0) {
+                x /= 5;
+                f[i][j][1]++;
+            }
+        }
+    }
+
+    for (int i = 1; i <= n; i++) {
+        for (int j = 1; j <= n; j++) {
+            // true => D
+            // false => R
+            if (i > 1 && j > 1) {
+                if (f[i - 1][j][0] < f[i][j - 1][0]) {
+                    g[i][j][0] = true;
+                    f[i][j][0] += f[i - 1][j][0];
+                } else {
+                    g[i][j][0] = false;
+                    f[i][j][0] += f[i][j - 1][0];
+                }
+
+                if (f[i - 1][j][1] < f[i][j - 1][1]) {
+                    g[i][j][1] = true;
+                    f[i][j][1] += f[i - 1][j][1];
+                } else {
+                    g[i][j][1] = false;
+                    f[i][j][1] += f[i][j - 1][1];
+                }
+            } else if (i > 1) {
+                g[i][j][0] = g[i][j][1] = true;
+                f[i][j][0] += f[i - 1][j][0];
+                f[i][j][1] += f[i - 1][j][1];
+            } else if (j > 1) {
+                g[i][j][0] = g[i][j][1] = false;
+                f[i][j][0] += f[i][j - 1][0];
+                f[i][j][1] += f[i][j - 1][1];
+            }
+        }
+    }
+
+    bool p = f[n][n][0] > f[n][n][1];
+
+    if (flag && f[n][n][p]) {
+        cout << 1 << endl;
+
+        for (int i = 1; i < zy; i++) {
+            cout << "R";
+        }
+
+        for (int i = 1; i < n; i++) {
+            cout << "D";
+        }
+
+        for (int i = zy; i < n; i++) {
+            cout << "R";
+        }
+
+        cout << endl;
+
+        exit(0);
+    }
+
+    int x = n, y = n;
+    std::string s;
+
+    cout << f[n][n][p] << endl;
+
+    while (x != 1 || y != 1) {
+        if (g[x][y][p]) {
+            s.push_back('D');
+            x--;
+        } else {
+            s.push_back('R');
+            y--;
+        }
+    }
+
+    std::reverse(s.begin(), s.end());
+
+    cout << s << endl;
+
+    return 0;
+}