var rand = (function() { var seed = 49734321; return function() { // Robert Jenkins' 32 bit integer hash function. seed = ((seed + 0x7ed55d16) + (seed << 12)) & 0xffffffff; seed = ((seed ^ 0xc761c23c) ^ (seed >>> 19)) & 0xffffffff; seed = ((seed + 0x165667b1) + (seed << 5)) & 0xffffffff; seed = ((seed + 0xd3a2646c) ^ (seed << 9)) & 0xffffffff; seed = ((seed + 0xfd7046c5) + (seed << 3)) & 0xffffffff; seed = ((seed ^ 0xb55a4f09) ^ (seed >>> 16)) & 0xffffffff; return (seed & 0xfffffff) / 0x10000000; }; })(); var map = {}, i = 1; var n = rand(); map[n] = true; n = rand(); while( !(n in map) ) { i++; map[n] = true; n = rand(); } console.log(i + ':' + n);
结果:16720次产生碰撞 : 0.06406551226973534