html 二进制搜索#jsbench #jsperf（https://jsbench.github.io/#bab89686622850413bb8d79a55a319da)#jsbench #jsp

Posted 2021-05-11

"use strict";

(function (factory) {
	if (typeof Benchmark !== "undefined") {
		factory(Benchmark);
	} else {
		factory(require("benchmark"));
	}
})(function (Benchmark) {
	var suite = new Benchmark.Suite;

	Benchmark.prototype.setup = function () {
		var BinarySearch = function (list, val) {
		  	var from = 0, to = list.length, cursor = Math.floor(from + (to - from) / 2);
		  	
		          while (list[cursor] !== val) {
		                  if (from == to) {
		                          return -1;
		                  } else {
		                          if (list[cursor] > val) {
		                                  to = cursor;
		                                  
		                          } else /*if (list[cursor] < val)*/ {
		                                  from = cursor;
		                          }
		                          
		                          cursor = Math.floor(from + (to - from) / 2);
		                  }
		          }
		          
		          return cursor;
		    };
		  
		  function BinarySearchBitshift3 (list, val) {
		  	var min = 0;
		  	var max = list.length;
		  	max--;
		  	
		  	while(true) // fall back to linear search, 11 seems to be a good threshold, but this depends on the uses comparator!! (here: ===)
		  	{   
		  	    if (min + 8 > max) break
		  		var mid = (min + max) >> 1;
		  		var dat = list[ mid ];
		  
		  		if ( val === dat ) return mid;
		  		
		  		if( val > dat ) {
		  			min = mid + 1;
		  		} else {
		  			max = mid - 1;
		  		}
		  	}
		  	while (max >= min) {
		        if( val === list[max] ) return max;
		        max--
		    }
		    return -1;
		  };
		  var BinarySearchBitshift = function (list, val) {
		  	var min = 0
		  	  , max = list.length-1
		  	  ;
		  	
		  	for(;;)
		  	{
		  		// fall back to linear search, 11 seems to be a good threshold, but this depends on the uses comparator!! (here: ===)
		  		if ( min + 11 > max ) {
		  			for(var i=min ; i<=max; i++ ) {
		  				if( val === list[i] ) {
		  					return i;
		  				}
		  			}
		  
		  			return -1;
		  		}
		  
		  		var mid = (min + max) >> 1;
		  		var dat = list[ mid ];
		  
		  		if ( val === dat ) {
		  			return mid;
		  		} 
		  
		  		if( val > dat ) {
		  			min = mid + 1;
		  		} else {
		  			max = mid - 1;
		  		}
		  	}
		  };
		  function  gt(x,y) {return  (y - x) >>> 31 }
		  
		  var bounds = new Uint32Array(2)
		  	
		  	
		  var BinarySearchBitshift2 = function (list, val) {
		  		var min = 0
		  	  , max = list.length-1
		  	  ;
		  	for(;;)
		  	{
		  	    
		  		// fall back to linear search, 11 seems to be a good threshold, but this depends on the uses comparator!! (here: ===)
		  	   	// fall back to linear search, 11 seems to be a good threshold, but this depends on the uses comparator!! (here: ===)
		  		if ( min + 11 > max ) {
		  			for(var i=min ; i<=max; i++ ) {
		  				if( val === list[i] ) {
		  					return i;
		  				}
		  			}
		  
		  			return -1;
		  		}
		  
		  		var mid = (min + max) >> 1;
		  		var dat = list[ mid ]
		        var v = dat - val
		  		
		  		if (v===0) return mid
		        
		        if (v >>> 31) {
		            max = mid - 1
		            
		        }else {
		            min = mid + 1
		        }
		
		  	}
		  };
		  
		  // http://codereview.stackexchange.com/questions/1480/better-more-efficient-way-of-writing-this-javascript-binary-search
		  var stackexchange = function (arr, ele) {
		        var beginning = 0, end = arr.length,
		            target;
		        while (true) {
		            target = ((beginning + end) >> 1);
		            if ((target === end || target === beginning) && arr[target] !== ele) {
		                return -1;
		            }
		            if (arr[target] > ele) {
		                end = target;
		            } else if (arr[target] < ele) {
		                beginning = target;
		            } else {
		                return target;
		            }
		        }
		    };
		    
		    
		function SEARCH (array, newItem) {
		  let insertIndex = -1
		  let minIndex = 0
		  let lastIndex = array.length - 1
		  let maxIndex = lastIndex
		  let i, item
		  while (insertIndex === -1) {
		    // bitshift right, `x >> 1` is equivalent to `Math.floor(x/2)`
		    i = ((maxIndex - minIndex + 1) >> 1) + minIndex
		    item = array[i]
		    if (newItem <= item) {
		      maxIndex = i
		      if (i === 0) return i
		      if (minIndex + 1 === maxIndex) return (newItem <= array[minIndex]) ? minIndex : i
		    }
		    else if (newItem > item) {
		      minIndex = i
		      if (i === lastIndex) return i
		      if (minIndex + 1 === maxIndex) return (newItem <= array[maxIndex]) ? maxIndex : maxIndex + 1
		    }
		  }
		}
		    
		    
		  
		  var data0 = [1];
		  var data1 = [1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 15, 65, 67, 98, 321, 651, 4000, 5000, 6000, 7000, 10000, 11000, 12000, 15000, 65000, 67000, 98000, 320001, 651000];
		  var data2 = [1, 2, 3, 4, 5, 6, 7, 435, 546, 765, 766, 7687, 345365];
		  var data3 = [];
		      for(var i=0;i<10000;i++) data3.push( i * i - i );
		  
		  var l0 = {}, l1 ={}, l2={}, l3={};
		  for(var i=0,m=data1.length;i<m;i++) l1[ data1[i] ] = i;
		  for(var i=0,m=data2.length;i<m;i++) l2[ data2[i] ] = i;
		  for(var i=0,m=data3.length;i<m;i++) l3[ data3[i] ] = i;
		  
		  typed0 = new Uint32Array(data0)
		  typed1 = new Uint32Array(data1)
		  typed2 = new Uint32Array(data2)
		  typed3 = new Uint32Array(data3)
	};


	suite.add("BinarySearchBitshift(data0, 0);", function () {
		BinarySearchBitshift(data0, 0);
		BinarySearchBitshift(data1, 1);
		BinarySearchBitshift(data2, 546);
		BinarySearchBitshift(data3, 1892);
		BinarySearchBitshift(data3, 49999);
		BinarySearchBitshift(data3, 4999);
	});

	suite.add("BinarySearchBitshift3(data0, 0);", function () {
		BinarySearchBitshift3(data0, 0);
		BinarySearchBitshift3(data1, 1);
		BinarySearchBitshift3(data2, 546);
		BinarySearchBitshift3(data3, 1892);
		BinarySearchBitshift3(data3, 49999);
		BinarySearchBitshift3(data3, 4999);
	});

	suite.add("BinarySearchBitshift(typed0, 0);", function () {
		BinarySearchBitshift(typed0, 0);
		BinarySearchBitshift(typed1, 1);
		BinarySearchBitshift(typed2, 546);
		BinarySearchBitshift(typed3, 1892);
		BinarySearchBitshift(typed3, 49999);
		BinarySearchBitshift(typed3, 4999);
	});

	suite.add("typed0.includes(0);", function () {
		typed0.includes(0);
		typed1.includes(1);
		typed2.includes(546);
		typed3.includes(1892);
		typed3.includes(49999);
		typed3.includes(4999);
	});

	suite.add("BinarySearchBitshift2(data0, 0);", function () {
		BinarySearchBitshift2(data0, 0);
		BinarySearchBitshift2(data1, 1);
		BinarySearchBitshift2(data2, 546);
		BinarySearchBitshift2(data3, 1892);
		BinarySearchBitshift2(data3, 49999);
		BinarySearchBitshift2(data3, 4999);
	});

	suite.add("BinarySearchBitshift2(typed0, 0);", function () {
		BinarySearchBitshift2(typed0, 0);
		BinarySearchBitshift2(typed1, 1);
		BinarySearchBitshift2(typed2, 546);
		BinarySearchBitshift2(typed3, 1892);
		BinarySearchBitshift2(typed3, 49999);
		BinarySearchBitshift2(typed3, 4999);
	});

	suite.add("data0.indexOf(0);", function () {
		data0.indexOf(0);
		data1.indexOf(1);
		data2.indexOf(546);
		data3.indexOf(1892);
		data3.indexOf(49999);
		data3.indexOf(4999);
	});

	suite.add("data0.includes(0);", function () {
		data0.includes(0);
		data1.includes(1);
		data2.includes(546);
		data3.includes(1892);
		data3.includes(49999);
		data3.includes(4999);
	});

	suite.on("cycle", function (evt) {
		console.log(" - " + evt.target);
	});

	suite.on("complete", function (evt) {
		console.log(new Array(30).join("-"));

		var results = evt.currentTarget.sort(function (a, b) {
			return b.hz - a.hz;
		});

		results.forEach(function (item) {
			console.log((idx + 1) + ". " + item);
		});
	});

	console.log("binary search #jsbench #jsperf");
	console.log(new Array(30).join("-"));
	suite.run();
});

<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8"/>
	<title>binary search #jsbench #jsperf</title>
	<script src="https://cdnjs.cloudflare.com/ajax/libs/benchmark/1.0.0/benchmark.min.js"></script>
	<script src="./suite.js"></script>
</head>
<body>
	<h1>Open the console to view the results</h1>
	<h2><code>cmd + alt + j</code> or <code>ctrl + alt + j</code></h2>
</body>
</html>