Given an unsorted integer array, find a pair with the given sum in it.

solution.js

/*

For example,

Input:
 
nums = [8, 7, 2, 5, 3, 1]
target = 10
 
Output:
 
Pair found (8, 2)
or
Pair found (7, 3)
 
 
Input:
 
nums = [5, 2, 6, 8, 1, 9]
target = 12
 
Output: Pair not found

*/

function getTargetIndexes(input) {
    const { array, target } = input;
    const hash = {};
    const results = [];
    for (let i = 0; i < array.length; i++) {
        const value = array[i];
        const pairReqdNum = target - value;
        const pairReqdIndex = hash[pairReqdNum];
        if (typeof pairReqdIndex !== 'undefined') {
            results.push([i, pairReqdIndex]);
        }
        hash[value] = i;
    }
    return results;
}

const testCases = [
  { input: { array: [4,8,0], target: 8 }, expectedOutput: [[1,0]] },
  { input: { array: [4,-3,80,1,13,9], target: 10 }, expectedOutput: [[1,4], [3,5]] }
];

for (testCase of testCases) {
  const actualOutput = getTargetIndexes(testCase.input);
  const { expectedOutput } = testCase;
  console.log('Test case report', {
    'I/P ': testCase.input,
    'O/P Expected': expectedOutput,
    'O/P Actual': actualOutput,
    'Result': JSON.stringify(expectedOutput) === JSON.stringify(actualOutput)
  );
}