leetcode

Author: ayoubzulfiqar

SearchA2DMatrix/search_a_2d_matrix.dart

@@ -0,0 +1,95 @@
+/*
+
+
+
+-* 74. Search a 2D Matrix *-
+
+You are given an m x n integer matrix matrix with the following two properties:
+
+Each row is sorted in non-decreasing order.
+The first integer of each row is greater than the last integer of the previous row.
+Given an integer target, return true if target is in matrix or false otherwise.
+
+You must write a solution in O(log(m * n)) time complexity.
+
+ 
+
+Example 1:
+
+
+Input: matrix = [[1,3,5,7],[10,11,16,20],[23,30,34,60]], target = 3
+Output: true
+Example 2:
+
+
+Input: matrix = [[1,3,5,7],[10,11,16,20],[23,30,34,60]], target = 13
+Output: false
+ 
+
+Constraints:
+
+m == matrix.length
+n == matrix[i].length
+1 <= m, n <= 100
+-104 <= matrix[i][j], target <= 104
+
+
+*/
+
+class A {
+  bool searchMatrix(List<List<int>> matrix, int target) {
+    final List<int> innerList =
+        matrix.expand((innerArray) => innerArray).toList();
+    return innerList.contains(target);
+  }
+}
+
+class Solution {
+  int search(List<int> v, int target) {
+    final int index = lowerBound(v, target);
+    return index;
+  }
+
+  bool searchMatrix(List<List<int>> matrix, int target) {
+    final int n = matrix.length;
+    final int m = matrix[0].length;
+
+    if (n == 1) {
+      final int j = search(matrix[0], target);
+      if (j == m) return false;
+      return matrix[0][j] == target;
+    }
+
+    final List<int> col0 = List<int>.generate(n, (i) => matrix[i][0]);
+
+    final int i0 = search(col0, target);
+
+    if (i0 == n) {
+      final int j = search(matrix[i0 - 1], target);
+      if (j == m) return false;
+      return matrix[i0 - 1][j] == target;
+    } else if (col0[i0] == target) {
+      return true;
+    } else if (i0 == 0) {
+      return false;
+    } else {
+      final int j = search(matrix[i0 - 1], target);
+      if (j == m) return false;
+      return matrix[i0 - 1][j] == target;
+    }
+  }
+
+  int lowerBound(List<int> array, int target) {
+    int left = 0;
+    int right = array.length;
+    while (left < right) {
+      int mid = left + (right - left) ~/ 2;
+      if (array[mid] < target) {
+        left = mid + 1;
+      } else {
+        right = mid;
+      }
+    }
+    return left;
+  }
+}

SearchA2DMatrix/search_a_2d_matrix.go

@@ -0,0 +1,58 @@
+package main
+
+func search(v []int, target int) int {
+	index := lowerBound(v, target)
+	return index
+}
+
+func searchMatrix(matrix [][]int, target int) bool {
+	n := len(matrix)
+	m := len(matrix[0])
+
+	if n == 1 {
+		j := search(matrix[0], target)
+		if j == m {
+			return false
+		}
+		return matrix[0][j] == target
+	}
+
+	col0 := make([]int, n)
+	for i := 0; i < n; i++ {
+		col0[i] = matrix[i][0]
+	}
+
+	i0 := search(col0, target)
+
+	if i0 == n {
+		j := search(matrix[i0-1], target)
+		if j == m {
+			return false
+		}
+		return matrix[i0-1][j] == target
+	} else if col0[i0] == target {
+		return true
+	} else if i0 == 0 {
+		return false
+	} else {
+		j := search(matrix[i0-1], target)
+		if j == m {
+			return false
+		}
+		return matrix[i0-1][j] == target
+	}
+}
+
+func lowerBound(array []int, target int) int {
+	left := 0
+	right := len(array)
+	for left < right {
+		mid := left + (right-left)/2
+		if array[mid] < target {
+			left = mid + 1
+		} else {
+			right = mid
+		}
+	}
+	return left
+}