"use strict";
let meteoZond = diffs => {
    let X = 0,
        Y = 0;
    for (let i = 0; i < diffs.length; i++) {
            X+=diffs[i][0]
            Y+=diffs[i][1]
    }
    if (X % 2 == 0 && Y % 2 == 0) {
        for(let i = 0; i < diffs.length/2; i++) {
            diffs[i][0]--;
            diffs[i][1]--;
                // if (diffs[i][0] != 0) diffs[i][0] = -diffs[i][0]
                // if (diffs[i][1] != 0) diffs[i][1] = -diffs[i][1]
        }
    }
    else
        return null
    return diffs
}

// let diffs = [
//     [1, 0],
//     [0, 1],
//     [1, 1]
// ];

//let diffs =  [[1,0], [1,0], [0,1], [0,1]];
let diffs = [[1,0], [0,1], [1,0], [0,1], [1,1], [1,1]]

let result = meteoZond(diffs);

console.log(result)