Leftmost Column with at Least a One

Description

null

Solution(javascript)

/**
 * // This is the BinaryMatrix's API interface.
 * // You should not implement it, or speculate about its implementation
 * function BinaryMatrix() {
 *     @param {integer} row, col
 *     @return {integer}
 *     this.get = function(row, col) {
 *         ...
 *     };
 *
 *     @return {[integer, integer]}
 *     this.dimensions = function() {
 *         ...
 *     };
 * };
 */

/**
 * @param {BinaryMatrix} binaryMatrix
 * @return {number}
 */
var leftMostColumnWithOne = function(binaryMatrix) {
    const [rows, columns] = binaryMatrix.dimensions()
    const getIndex = (row) => {
        let result = -1
        let left = 0
        let right = columns - 1
        while(left <= right) {
            const middle = Math.floor(left + (right - left) / 2)
            const value = binaryMatrix.get(row, middle)
            if(value < 1) {
                left = middle + 1
            } else {
                right = middle - 1
                result = middle
            }
        }
        return result
    }
    let result = -1
    for(let row = 0; row < rows; row ++) {
        const index = getIndex(row)
        if(index !== -1) {
            if(result !== -1) {
                result = Math.min(index, result)   
            } else {
                result = index
            }
        }
    }
    return result
};