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Next String (using counting sort)
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function nextLex(str) { | |
var breakIndex = -1; | |
var chars = str.split(""); | |
for (var i=chars.length-1; i>0; i--) { | |
if (chars[i] > chars[i-1]) { | |
breakIndex = i-1; | |
break; | |
} | |
} | |
if (breakIndex > -1) { | |
var swapIndex = breakIndex + 1; | |
for (var i=swapIndex+1; i<chars.length; i++) { | |
if (chars[i] > str[breakIndex] && chars[i] < chars[swapIndex]) { | |
swapIndex = i; | |
} | |
} | |
swap(breakIndex, swapIndex, chars); | |
chars = countingSort(chars, breakIndex+1, chars.length-1); | |
} | |
return chars.join(""); | |
} | |
function countingSort(array, start, end) { | |
var b = []; | |
for (var i=0;i<26;i++) { | |
b.push(0); | |
} | |
var aCode = 'a'.charCodeAt(0); | |
for (var i=start; i<=end; i++) { | |
var idx = (array[i].charCodeAt(0) - aCode)%26; | |
b[idx]++; | |
} | |
var right = []; | |
for (var i=0;i<b.length;i++){ | |
var x = b[i]; | |
while (x>0){ | |
right.push(String.fromCharCode(aCode+i)); | |
x--; | |
} | |
} | |
array.splice(start); | |
array = array.concat(right); | |
return array; | |
} | |
function swap(i, j, array) { | |
var temp = array[i]; | |
array[i] = array[j]; | |
array[j] = temp; | |
} | |
nextLex("xyzafedcb"); |
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The use of counting sort will be much faster.