class Solution {
    public int[][] restoreMatrix(int[] rowSum, int[] colSum) {
        int rowLen = rowSum.length;
        int colLen = colSum.length;

        int[][] ans = new int[rowLen][colLen];

        int row = 0, col = 0;

        while (row < rowLen && col < colLen) {
            int min = Math.min(colSum[col], rowSum[row]);
            ans[row][col] = min;
            colSum[col] -= min;
            rowSum[row] -= min;

            if (rowSum[row] == 0)
                row++;
            if (colSum[col] == 0)
                col++;
        }

        return ans;
    }
}