基礎連結串列演算法
阿新 • • 發佈：2022-04-02
1 class NodeMake{ 2 constructor(){ 3 this.value=null; 4 this.next=null; 5 } 6 } 7 //隨機指標節點 8 class NodeMakeRandom{ 9 constructor(){ 10 this.value=null; 11 this.next=null; 12 this.random=null; 13 } 14 Clone(Node){ 15 this.value=Node.value; 16 this.next=Node.next; 17 this.random=Node.random; 18 } 19 } 20 function MakeLink(){ 21 let head=new NodeMake(); 22 for(let i=0;i<=5;i++){ 23 let tmpval= Math.floor(Math.random()*10); 24 let p= new NodeMake(); 25 p.value=tmpval;26 p.next=head.next; 27 head.next=p; 28 } 29 30 return head.next; 31 } 32 33 function output(head){ 34 let p=head; 35 while(p){ 36 console.log(p.value); 37 p=p.next; 38 } 39 } 40 //用頭插法實現反轉連結串列 41 function ReverseLink(head){ 42 if(head.next==null){ 43 return head; 44 } 45 let new_head=new NodeMake(); 46 let p=head; 47 while(p){ 48 let tmp=p.next; 49 p.next=new_head.next 50 new_head.next=p; 51 p=tmp; 52 } 53 return new_head.next; 54 55 } 56 //判斷迴文，用壓棧方式快速解決 57 function JudegePal1(head){ 58 let stack =new Array(); 59 let p=head; 60 while(p){ 61 if(p.value==stack[0]){ 62 stack.shift(); 63 } 64 else{ 65 stack.unshift(p.value); 66 } 67 p=p.next; 68 } 69 if(stack.length==0||stack.length==1){ 70 console.log("是迴文"); 71 } 72 else{ 73 console.log("不是迴文"); 74 } 75 76 } 77 //判斷迴文，用快慢指標減少空間複雜度 78 function JudegePal2(head){ 79 let slow=head; 80 let fast=head; 81 while(fast&&fast.next){ 82 slow=slow.next; 83 fast=fast.next.next; 84 } 85 //若連結串列只有一個值時返回 86 if(fast==head){ 87 console.log("是迴文"); 88 return; 89 } 90 //從slow節點反轉連結串列，從首尾逼近比較 91 let Tail=ReverseLink(slow); 92 let FromTail=Tail; 93 let FromHead=head; 94 let flag=1; 95 while(FromHead&&FromTail){ 96 if(FromHead.value!=FromTail.value){ 97 flag=0; 98 break; 99 } 100 FromHead=FromHead.next; 101 FromTail=FromTail.next; 102 } 103 ReverseLink(Tail); 104 if(flag){ 105 console.log("是迴文"); 106 } 107 else{ 108 console.log("不是迴文"); 109 } 110 111 112 } 113 //單鏈表的荷蘭國旗問題 114 //用陣列快速解決 115 function LessEqualMore1(head,num){ 116 let arr=new Array(); 117 let p=head; 118 while(p){ 119 arr.push(p); 120 p=p.next; 121 } 122 GuoQi(arr,num); 123 head=arr[0]; 124 let i; 125 for(i=0;i<=arr.length-2;i++){ 126 arr[i].next=arr[i+1]; 127 } 128 arr[i].next=null; 129 } 130 function GuoQi(arr,num){ 131 let less,more,i; 132 less=-1;more=arr.length;i=0; 133 while(i<more){ 134 if(arr[i].value<num){ 135 less++; 136 swap(arr,i,less); 137 i++; 138 } 139 else if(arr[i].value>num){ 140 more--; 141 swap(arr,i,more); 142 } 143 else{ 144 i++; 145 } 146 } 147 } 148 function swap(arr,p1,p2){ 149 [arr[p1],arr[p2]]=[arr[p2],arr[p1]]; 150 } 151 //用六個變數標誌各個區域頭尾，減少空間複雜度 152 function LessEqualMore2(head,num){ 153 let LessStart,LessEnd,EqualStart,EqualEnd,MoreStart,MoreEnd; 154 let p=head; 155 let new_head; 156 while(p){ 157 if(p.value<num){ 158 let tmp=p; 159 p=p.next; 160 if(LessStart==null){ 161 LessStart=tmp; 162 LessEnd=tmp; 163 LessEnd.next=null; 164 continue; 165 } 166 let sign=LessEnd; 167 LessEnd=tmp; 168 sign.next=LessEnd; 169 LessEnd.next=null; 170 } 171 else if(p.value>num){ 172 let tmp=p; 173 p=p.next; 174 if(MoreStart==null){ 175 MoreStart=tmp; 176 MoreEnd=tmp; 177 MoreEnd.next=null; 178 continue; 179 } 180 let sign=MoreEnd; 181 MoreEnd=tmp; 182 sign.next=MoreEnd; 183 MoreEnd.next=null; 184 } 185 else{ 186 let tmp=p; 187 p=p.next; 188 if(EqualStart==null){ 189 EqualStart=tmp; 190 EqualEnd=tmp; 191 EqualEnd.next=null; 192 continue; 193 } 194 let sign =EqualEnd; 195 EqualEnd=tmp; 196 sign.next=EqualEnd; 197 EqualEnd.next=null; 198 } 199 200 } 201 if(LessStart){ 202 if(EqualStart){ 203 LessEnd.next=EqualStart; 204 EqualEnd.next=MoreStart; 205 } 206 else{ 207 LessEnd.next=MoreStart; 208 } 209 new_head=LessStart; 210 } 211 else if(EqualStart){ 212 EqualEnd.next=MoreStart; 213 new_head=EqualStart; 214 } 215 else{ 216 new_head=MoreStart; 217 } 218 return new_head; 219 } 220 //隨即指標連結串列的複製 221 //用雜湊錶快速解決 222 function CopyLink1(head){ 223 let p=head; 224 let HashMap=new Map(); 225 while(p){ 226 let clone=p; 227 HashMap.set(p,clone); 228 p=p.next; 229 } 230 p=head; 231 while(p){ 232 let clone=HashMap.get(p); 233 clone.next=HashMap.get(p.next); 234 clone.random=HashMap.get(p.random); 235 p=p.next; 236 } 237 return HashMap.get(head); 238 } 239 //用克隆節點直接掛節省空間 240 function CopyLink2(head){ 241 let p=head; 242 while(p){ 243 let sign=p; 244 p=p.next; 245 let clone=new NodeMakeRandom; 246 clone.Clone(sign); 247 sign.next=clone; 248 clone.next=p; 249 } 250 p=head; 251 let new_head; 252 new_head=p.next; 253 let tmp=new_head; 254 while(p){ 255 let sign=p; 256 p=p.next.next; 257 if(tmp.random){ 258 tmp.random=tmp.random.next; 259 } 260 if(p){ 261 tmp.next=p.next; 262 tmp=tmp.next; 263 } 264 sign.next=p; 265 } 266 return new_head; 267 268 } 269 //判斷兩個有可能有環的單鏈表是否相交 270 function JudgeIntersect(head1,head2){ 271 let loop1,loop2; 272 loop1=JudgeLoop(head1);loop2=JudgeLoop(head2); 273 //一個有環一個無環的單鏈表是不可能有交點的 274 if((loop1==null&&loop2!=null)||(loop1!=null&&loop2==null)){ 275 console.log("沒有交點"); 276 return; 277 } 278 else if(loop1==null&&loop2==null){//兩個無環的單鏈表 279 let end1,end2,length; 280 end1=head1;end2=head2;length=0; 281 while(end1.next){ 282 end1=end1.next; 283 length++; 284 } 285 while(end2.next){ 286 end2=end2.next; 287 length--; 288 } 289 if(end1!=end2){//終點不同的兩個單鏈表是不會有交點的 290 console.log("沒有交點"); 291 return; 292 } 293 else{ 294 let cur1=length>=0?head1:head2;//cur1存放長的那個連結串列 295 let cur2=cur1==head1?head2:head1; 296 length=Math.abs(length); 297 for(let i=1;i<=length;i++){ 298 cur1=cur1.next; 299 } 300 while(cur1!=cur2){ 301 cur1=cur1.next; 302 cur2=cur2.next; 303 } 304 console.log("交點是"+cur1.value); 305 return ; 306 } 307 } 308 else{//兩個有環的單鏈表 309 if(loop1==loop2){//環的第一個點相同，相當於兩個無環單鏈表 310 let end1,end2,length; 311 end1=head1;end2=head2; 312 while(end1!=loop1.next){ 313 end1=end1.next; 314 length++; 315 } 316 while(end2!=loop1.next){ 317 end2=end2.next; 318 length--; 319 } 320 let cur1=length>=0?head1:head2;//cur1存放長的那個連結串列 321 let cur2=cur1==head1?head2:head1; 322 length=Math.abs(length); 323 for(let i=1;i<=length;i++){ 324 cur1=cur1.next; 325 } 326 while(cur1!=cur2){ 327 cur1=cur1.next; 328 cur2=cur2.next; 329 } 330 console.log("交點是"+cur1.value); 331 return 332 } 333 else{//快慢指標判斷交點不同的情況 334 let time=0; 335 let slow,fsat; 336 slow=loop1.next;fast=loop2.next.next; 337 while(slow!=fast){ 338 if(fast==loop2||fast.next==loop2){ 339 time++; 340 } 341 if(time>=3){ 342 console.log("沒有交點"); 343 return; 344 } 345 slow=slow.next;fast=fast.next.next; 346 } 347 console.log("兩個交點"+loop1.value+loop2.value); 348 return; 349 } 350 351 } 352 353 } 354 //快慢指標判斷單鏈表有無環 355 function JudgeLoop(head){ 356 if(head.next==null){ 357 return null; 358 } 359 let slow,fast; 360 slow=head.next;fast=head.next.next; 361 while(slow!=fast){ 362 slow=slow.next; 363 if(fast&&fast.next){ 364 fast=fast.next.next; 365 } 366 else{ 367 console.log("無環"); 368 return null; 369 } 370 } 371 fast=head; 372 while(slow!=fast){ 373 slow=slow.next; 374 fast=fast.next; 375 } 376 console.log("環的第一個點是"+slow.value); 377 return slow; 378 } 379 380 //一些測試資料 381 let head1=MakeLink(); 382 let head2=MakeLink(); 383 //output(head); 384 // JudegePal2(head); 385 //LessEqualMore1(head,2); 386 // output(head); 387 // console.log("*************"); 388 // // JudegePal1(head); 389 // head=LessEqualMore2(head,2); 390 // head.random=head.next.next; 391 // console.log("*************"); 392 // head = CopyLink2(head); 393 // output(head); 394 // output(head.random); 395 // output(head1); 396 // console.log("*************"); 397 // output(head2); 398 head1.next.next.next.next=head2.next; 399 head2.next.next.next.next=head1.next; 400 // output(head1); 401 // console.log("*************"); 402 // output(head2); 403 JudgeIntersect(head1,head2);