在 O(n^2) 时间内找到给定字符串的所有子字符串。

function genSubstrings ( inputString ){ debugger ; let resultArray = []; // outer loop to run n times [n = size of string] for ( let i = 0 ; i < inputString . length ; i ++ ){ // pushing first char of string as substring // as we know that each char will be substring itself too. resultArray . push ( inputString [ i ]); // inner loop to run n - 1 times; for ( let j = i + 1 ; j < inputString . length ; j ++ ){ // get last substring and append the new next char resultArray . push ( resultArray [ resultArray . length - 1 ] + inputString [ j ] ); } } return resultArray ; }

genSubstrings ( " abcd " ); ( 10 ) [ ' a ' , ' ab ' , ' abc ' , ' abcd ' , ' b ' , ' bc ' , ' bcd ' , ' c ' , ' cd ' , ' d ' ]