competitive-programming/Matrix/SpiralMatrix2.java at master · kothariji/competitive-programming · GitHub

35 lines (30 loc) · 954 Bytes

class Solution {

public int[][] generateMatrix(int n) {

int matrix[][] = new int[n][n];

int val = 1;

int left = 0, right = matrix[0].length-1, top = 0,bottom = matrix.length-1;

while((left <= right) && (top <= bottom)) {

for(int i = left ; i <= right; i++) {

matrix[top][i] = val++;

}

top++;

for(int i = top ; i <= bottom ; i++) {

matrix[i][right] = val++;

}

right--;

if(top <= bottom) {

for(int i = right; i >= left ; i--) {

matrix[bottom][i] = val++;

}

bottom --;

if(left <= right) {

for(int i = bottom; i >= top ; i--) {

matrix[i][left] = val++;

}

left++;

}

return matrix;

}

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