JavaScript的- 673 707 730 751
e=[],g=[],h=[],m=[],q=[];function r(){a=s,b=t;function d(d,A){n=a+d,p=b+A;c>e[n][p]&&(u=!1,v>e[n][p]&&(v=e[n][p],w=n,k=p))}c=e[a][b],u=!0,v=c,w=a,k=b;0!=a&&d(-1,0);a!=l&&d(1,0);0!=b&&d(0,-1);b!=l&&d(0,1);g[a][b]=w;h[a][b]=k;return u}function x(a,b,d){function c(a,b,c,k){g[a+b][c+k]==a&&h[a+b][c+k]==c&&(d=x(a+b,c+k,d))}d++;0!=a&&c(a,-1,b,0);a!=l&&c(a,1,b,0);0!=b&&c(a,0,b,-1);b!=l&&c(a,0,b,1);return d}y=$EXEC('cat "'+$ARG[0]+'"').split("\n");l=y[0]-1;for(z=-1;z++<l;)e[z]=y[z+1].split(" "),g[z]=[],h[z]=[];for(s=-1;s++<l;)for(t=-1;t++<l;)r()&&m.push([s,t]);for(z=m.length-1;0<=z;--z)s=m[z][0],t=m[z][1],q.push(x(s,t,0));print(q.sort(function(a,b){return b-a}).join(" "));
测试结果(使用Nashorn):
$ for i in A B C D; do jjs -scripting minlm.js -- "test$i"; done
7 2
1
11 7 7
7 5 4
$
大小为5000的地图可能会有堆栈问题(但这是实现细节:)。
毫无根据的来源是模糊的:
// lm.js - find the local minima
// Globalization of variables.
/*
The map is a 2 dimensional array. Indices for the elements map as:
[0,0] ... [0,n]
...
[n,0] ... [n,n]
Each element of the array is a structure. The structure for each element is:
Item Purpose Range Comment
---- ------- ----- -------
h Height of cell integers
s Is it a sink? boolean
x X of downhill cell (0..maxIndex) if s is true, x&y point to self
y Y of downhill cell (0..maxIndex)
Debugging only:
b Basin name ('A'..'A'+# of basins)
Use a separate array-of-arrays for each structure item. The index range is
0..maxIndex.
*/
var height = [];
var sink = [];
var downhillX = [];
var downhillY = [];
//var basin = [];
var maxIndex;
// A list of sinks in the map. Each element is an array of [ x, y ], where
// both x & y are in the range 0..maxIndex.
var basinList = [];
// An unordered list of basin sizes.
var basinSize = [];
// Functions.
function isSink(x,y) {
var myHeight = height[x][y];
var imaSink = true;
var bestDownhillHeight = myHeight;
var bestDownhillX = x;
var bestDownhillY = y;
/*
Visit the neighbors. If this cell is the lowest, then it's the
sink. If not, find the steepest downhill direction.
This would be the place to test the assumption that "If a cell
is not a sink, you may assume it has a unique lowest neighbor and
that this neighbor will be lower than the cell." But right now, we'll
take that on faith.
*/
function visit(deltaX,deltaY) {
var neighborX = x+deltaX;
var neighborY = y+deltaY;
if (myHeight > height[neighborX][neighborY]) {
imaSink = false;
if (bestDownhillHeight > height[neighborX][neighborY]) {
bestDownhillHeight = height[neighborX][neighborY];
bestDownhillX = neighborX;
bestDownhillY = neighborY;
}
}
}
if (x !== 0) {
// upwards neighbor exists
visit(-1,0);
}
if (x !== maxIndex) {
// downwards neighbor exists
visit(1,0);
}
if (y !== 0) {
// left-hand neighbor exists
visit(0,-1);
}
if (y !== maxIndex) {
// right-hand neighbor exists
visit(0,1);
}
downhillX[x][y] = bestDownhillX;
downhillY[x][y] = bestDownhillY;
return imaSink;
}
function exploreBasin(x,y,currentSize) {//,basinName) {
// This cell is in the basin.
//basin[x][y] = basinName;
currentSize++;
/*
Visit all neighbors that have this cell as the best downhill
path and add them to the basin.
*/
function visit(x,deltaX,y,deltaY) {
if ((downhillX[x+deltaX][y+deltaY] === x) && (downhillY[x+deltaX][y+deltaY] === y)) {
currentSize = exploreBasin(x+deltaX,y+deltaY,currentSize); //,basinName);
}
return 0;
}
if (x !== 0) {
// upwards neighbor exists
visit(x,-1,y,0);
}
if (x !== maxIndex) {
// downwards neighbor exists
visit(x,1,y,0);
}
if (y !== 0) {
// left-hand neighbor exists
visit(x,0,y,-1);
}
if (y !== maxIndex) {
// right-hand neighbor exists
visit(x,0,y,1);
}
return currentSize;
}
// Read map from file (1st argument).
var lines = $EXEC('cat "' + $ARG[0] + '"').split('\n');
maxIndex = lines.shift() - 1;
for (var i = 0; i<=maxIndex; i++) {
height[i] = lines.shift().split(' ');
// Create all other 2D arrays.
sink[i] = [];
downhillX[i] = [];
downhillY[i] = [];
//basin[i] = [];
}
// Everyone decides if they are a sink. Create list of sinks (i.e. roots).
for (var x=0; x<=maxIndex; x++) {
for (var y=0; y<=maxIndex; y++) {
if (sink[x][y] = isSink(x,y)) {
// This node is a root (AKA sink).
basinList.push([x,y]);
}
}
}
//for (var i = 0; i<=maxIndex; i++) { print(sink[i]); }
// Each root explores it's basin.
//var basinName = 'A';
for (var i=basinList.length-1; i>=0; --i) { // i-- makes Closure Compiler sad
var x = basinList[i][0];
var y = basinList[i][1];
basinSize.push(exploreBasin(x,y,0)); //,basinName));
//basinName = String.fromCharCode(basinName.charCodeAt() + 1);
}
//for (var i = 0; i<=maxIndex; i++) { print(basin[i]); }
// Done.
print(basinSize.sort(function(a, b){return b-a}).join(' '));
通过将元素对象分解为单独的数组,在所有可能的地方全球化并包含副作用,我获得了更好的最小化结果。NSFW。
代码最小化的效果:
- 4537字节,未压缩
- 1180字节, 打包程序
- 855字节,打包程序+手动优化(1个字符的全局名称)
- 751字节,带有ADVANCED_OPTIMIZATIONS的Google Closure编译器(注意,它消除了残留的“返回0”作为无效代码)
- 730字节,不计后果的手动优化(我没有更改未缩小的源,所以NSFW)
- 707个字节,更不计后果的手动优化(删除对sink []的所有引用);
- 673个字节,删除所有“ var”,删除Nashorn -strict标志
如果我愿意修改原始源代码,那么无需编辑最小化的代码,我本可以达到近700个字节。但是我没有这样做,因为我认为从一开始就将其保留为一个有趣的观点。