Add C++ solutions for leetcode 62 and leetcode 63.

Author: yanglr

cpp-leetcode/leetcode62-unique-paths_dp.cpp

@@ -0,0 +1,37 @@
+#include<vector>
+#include<algorithm>
+#include<iostream>
+#include<cstring>
+using namespace std;
+
+class Solution {
+public:
+    int uniquePaths(int m, int n) {
+        int dp[m][n]; // dp数组 - dp[i][j]: 从位置(0, 0)走到位置(i, j)的unique path的数量
+        memset(dp, 0, sizeof(dp));
+        dp[0][0] = 1; /* 原点位置(0, 0)只有不动这一种走法, 对矩阵中间某个位置 dp[i][j] = dp[i-1][j] + dp[i][j-1] */
+        for (int i = 0; i < m; i++)
+        {
+            for (int j = 0; j < n; j++)
+            {
+                if (i >= 1) 
+                    dp[i][j] += dp[i-1][j];
+                if (j >= 1)
+                    dp[i][j] += dp[i][j-1];
+            }
+        }
+        return dp[m - 1][n - 1];
+    }
+};
+
+// Test
+int main()
+{
+    Solution sol;
+    int m = 3;
+    int n = 7;
+    auto res = sol.uniquePaths(m, n);
+    cout << res << endl;
+
+    return 0;
+}

cpp-leetcode/leetcode63-unique-paths-ii_dp.cpp

@@ -0,0 +1,48 @@
+#include<vector>
+#include<algorithm>
+#include<iostream>
+#include<cstring>
+using namespace std;
+
+class Solution {
+public:
+    int uniquePathsWithObstacles(vector<vector<int>>& G) {
+        const int m = G.size();
+        const int n = G[0].size();
+        int dp[m][n]; // dp数组 - dp[i][j]: 从位置(0, 0)走到位置(i, j)的unique path的数量
+        memset(dp, 0, sizeof(dp));
+        dp[0][0] = 1; /* 原点位置(0, 0)只有不动这1种走法, 对矩阵中间某个位置 dp[i][j] = dp[i-1][j] + dp[i][j-1] */
+        for (int i = 0; i < m; i++)
+        {
+            for (int j = 0; j < n; j++)
+            {
+                if (G[i][j] == 1)
+                    dp[i][j] = 0;
+                else 
+                {
+                    if (i >= 1)
+                        dp[i][j] += dp[i-1][j];
+                    if (j >= 1)
+                        dp[i][j] += dp[i][j-1];
+                }
+            }
+        }
+        return dp[m-1][n-1];
+    }
+};
+
+// Test
+int main()
+{
+    Solution sol;
+    vector<vector<int>> G =
+    {
+        {0, 0, 0},
+        {0, 1, 0},
+        {0, 0, 0}
+    };
+    auto res = sol.uniquePathsWithObstacles(G);
+    cout << res << endl;
+    
+    return 0;
+}