algos de permutations et combinaisons dans le tools.js

Author: Coldknife2

TOOLS/NodeJS/src/tools.js

@@ -91,4 +91,51 @@ export const substractTwoArrsMinZero = (arr1, arr2) => operateTwoArrs(arr1, arr2
 export const divideTwoArrsFloor = (arr1, arr2) => operateTwoArrs(arr1, arr2, (a,b) => Math.floor(a/b));
 
 export const smallestInArr = arr => Math.floor(arr.sort(sortAsc)[0]);
-export const biggestInArr = arr => Math.floor(arr.sort(sortDesc)[0]);
+export const biggestInArr = arr => Math.floor(arr.sort(sortDesc)[0]);
+
+// http://homepage.math.uiowa.edu/~goodman/22m150.dir/2007/Permutation%20Generation%20Methods.pdf Heap method
+export function permutations(permutation) {
+ var length = permutation.length,
+ result = [permutation.slice()],
+ c = new Array(length).fill(0),
+ i = 1, k, p;
+ 
+ while (i < length) {
+ if (c[i] < i) {
+ k = i % 2 && c[i];
+ p = permutation[i];
+ permutation[i] = permutation[k];
+ permutation[k] = p;
+ ++c[i];
+ i = 1;
+ result.push(permutation.slice());
+ } else {
+ c[i] = 0;
+ ++i;
+ }
+ }
+ return result;
+ }
+
+ function genererCombinaisons(tableau, tailleMin=0, tailleMax=tableau.length) {
+ let combinaisons = [];
+ for(let i = 0; i < 2**tableau.length; i++)
+ {
+ let combinaison = [];
+ let mask = i;
+ let nombresDeUn = i.toString(2).split`1`.length - 1;
+ if( nombresDeUn >= tailleMin && nombresDeUn <= tailleMax )
+ {
+ for(let j = 0; j < tableau.length; j++)
+ {
+ if(mask & 1)
+ {
+ combinaison.push(tableau[j]);
+ }
+ mask = mask >> 1;
+ }
+ combinaisons.push(combinaison);
+ }
+ }
+ return combinaisons;
+}