Day 70 by admin

Day 70/Count Binary Strings With No Consecutive 1s_GFG/Count_Binary_Strings_With_No_Consecutive_1s.cpp

@@ -0,0 +1,40 @@
+// Java Solution
+
+class Solution {
+    public int mod = 1000000007;
+    public void multiply(int[][] a, int[][] b) {
+        int mul[][] = new int[3][3];
+        for (int i = 0; i < 3; i++) {
+            for (int j = 0; j < 3; j++) {
+                for (int k = 0; k < 3; k++) {
+                    long temp = ((long)a[i][k] * b[k][j]) % mod;
+                    mul[i][j] += temp;
+                    mul[i][j] %= mod;
+                }
+            }
+        }
+        for (int i = 0; i < 3; i++) {
+            for (int j = 0; j < 3; j++) {
+                a[i][j] = mul[i][j];
+            }
+        }
+    }
+    public int power(int[][] mat, long N) {
+        int M[][] = {{1, 1, 0}, {1, 0, 0}, {0, 1, 0}};
+        if (N == 1) {
+            return (mat[0][0] + mat[0][1]) % mod;
+        }
+        power(mat, N / 2);
+        multiply(mat, mat);
+        if (N % 2 != 0) {
+            multiply(mat, M);
+        }
+        return (mat[0][0] + mat[0][1]) % mod;
+    }
+    int countStrings(long N) {
+        int[][] mat = {{1, 1, 0}, {1, 0, 0}, {0, 1, 0}};
+        if (N == 2) return 3;
+        if (N == 1) return 2;
+        return power(mat, N);
+    }
+}

Day 70/Spiral Matrix_Leetcode/Spiral_Matrix.cpp

@@ -0,0 +1,30 @@
+class Solution {
+ public:
+  vector<int> spiralOrder(vector<vector<int>>& matrix) {
+    if (matrix.empty())
+      return {};
+
+    const int m = matrix.size();
+    const int n = matrix[0].size();
+    vector<int> ans;
+    int r1 = 0;
+    int c1 = 0;
+    int r2 = m - 1;
+    int c2 = n - 1;
+
+    // Repeatedly add matrix[r1..r2][c1..c2] to ans
+    while (ans.size() < m * n) {
+      for (int j = c1; j <= c2 && ans.size() < m * n; ++j)
+        ans.push_back(matrix[r1][j]);
+      for (int i = r1 + 1; i <= r2 - 1 && ans.size() < m * n; ++i)
+        ans.push_back(matrix[i][c2]);
+      for (int j = c2; j >= c1 && ans.size() < m * n; --j)
+        ans.push_back(matrix[r2][j]);
+      for (int i = r2 - 1; i >= r1 + 1 && ans.size() < m * n; --i)
+        ans.push_back(matrix[i][c1]);
+      ++r1, ++c1, --r2, --c2;
+    }
+
+    return ans;
+  }
+};