Daily Coding Problem #5

dcp5.js

function getAnagram( word, string ) {
	let t1 = performance.now()
	let res = [];
	let word_array = word.split( '' );
	for ( let i of [ ...Array( string.length - word.length + 1 ).keys() ] ) {
		let a_window = string.substring( i, i + word.length );
		let a_window_array = a_window.split( '' );
		if ( JSON.stringify( word_array ) == JSON.stringify( a_window_array ) ||
			JSON.stringify( word_array ) == JSON.stringify( a_window_array.reverse() )
		) {
			res.push( i );
		}
	}
	let t2 = performance.now();
	let t = t2 - t1;
	return { res, t };
}
console.log( getAnagram( 'ab', 'abxaba' ) )

function getAnagram2( word, string ) {
	let t1 = performance.now()

	function delIfZero( dict, char ) {
		if ( dict[ char ] == 0 ) {
			delete dict[ char ]
		}
	}
	let res = [];
	let freq = {};
	for ( let i of word ) {
		freq[ i ] = freq[ i ] ? freq[ i ] + 1 : 1;
	}
	console.log( freq )
	for ( let i of string.substring( 0, word.length ) ) {
		freq[ i ] = freq[ i ] ? freq[ i ] - 1 : -1;
		delIfZero( freq, i );
	}
	if ( Object.entries( freq ).length === 0 ) {
		res.push( 0 )
	}
	for ( let i of [ ...Array( string.length ).keys() ].map( i => i + word.length ) ) {
		let start_char = string[ i - word.length ],
			end_char = string[ i ];
		freq[ start_char ] = freq[ start_char ] ? freq[ start_char ] + 1 : 1;
		delIfZero( freq, start_char );

		freq[ end_char ] = freq[ end_char ] ? freq[ end_char ] - 1 : -1;
		delIfZero( freq, end_char );
		if ( Object.entries( freq ).length === 0 ) {
			let beginning_index = i - word.length + 1;
			res.push( beginning_index );
		}
	}
	let t2 = performance.now();
	let t = t2 - t1;
	return { res, t };
}

console.log( getAnagram2( 'ab', 'abxaba' ) )