化学方程式-ccf

  1 package yrc1;
  2 import java.util.*;
  3 
  4 /**
  5  * 只获得60分，还需要完善
  6  * 算法思想：
  7  * 
  8  * 2、使用52位长度的整型数组作为辅助。检索左字符串时，记录字母在字符串中出现的次数；
  9  * 检索右字符串时，减去字母在字符串中出现的次数。
 10  *
 11  *      (1)通过"+"将字符串分割为多个表达式
 12  */
 13 public class Main4 {
 14     public static  void main(String args[]) {
 15         Scanner in = new Scanner(System.in);
 16         int n = in.nextInt();
 17         in.nextLine();
 18 
 19         while(n>0){
 20             String str = in.nextLine();
 21             String[] one = str.split("=");
 22             String left  = one[0];
 23             String right = one[1];
 24             int[] dp = new int[52];
 25             String[] leftson;
 26 
 27             if(left.contains("+")){
 28                 leftson = left.split("\\+");
 29             }else{
 30                 leftson = new String[1];
 31                 leftson[0] = left;
 32             }
 33             for(int i=0;i<leftson.length;i++){
 34                 int bs = 1;
 35 
 36                 if(Character.isDigit(leftson[i].charAt(0))){
 37                     bs = leftson[i].charAt(0)-‘0‘;
 38                     int j=1;
 39                     for(;j<leftson[i].length() && Character.isDigit(leftson[i].charAt(j));j++){
 40                         bs = bs*10+leftson[i].charAt(j)-‘0‘;
 41                     }
 42                     leftson[i] = leftson[i].substring(j);
 43                 }
 44                 fun1(dp,bs,leftson[i]);
 45             }
 46 
 47             String[] rightson;
 48             if(right.contains("+")){
 49                 rightson = right.split("\\+");
 50             }else{
 51                 rightson = new String[1];
 52                 rightson[0] = right;
 53             }
 54             for(int i=0;i<rightson.length;i++){
 55                 int bs = 1;
 56                 if(Character.isDigit(rightson[i].charAt(0))){
 57                     bs = rightson[i].charAt(0)-‘0‘;
 58                     int j=1;
 59                     for(;j<rightson[i].length() && Character.isDigit(rightson[i].charAt(j));j++){
 60                         bs = bs*10+rightson[i].charAt(j)-‘0‘;
 61                     }
 62                     rightson[i] = rightson[i].substring(j);
 63                 }
 64                 fun1(dp,-bs,rightson[i]);
 65             }
 66 
 67 
 68             //a-z:97-122,A-Z:65-90,0-9:48-57
 69             boolean flag = true;
 70             for(int i=0;i<dp.length;i++){
 71                 if(dp[i]!=0){
 72                     flag = false;
 73                     break;
 74                 }
 75             }
 76 
 77             if(flag){
 78                 System.out.println("Y");
 79             }else{
 80                 System.out.println("N");
 81             }
 82             n--;
 83         }
 84     }
 85     //只处理了嵌套括号，没有处理平行括号
 86     public static void fun1(int[] dp,int bs,String str){
 87         Stack<Character> charStack = new Stack<>();
 88         for(int i=0;i<str.length();i++){
 89             char c = str.charAt(i);
 90             if(Character.isDigit(c)){      //处理非个位数
 91                 int res = c-‘0‘;
 92                 int j=i+1;
 93                 for(;j<str.length() && Character.isDigit(str.charAt(j));j++){
 94                     res = res*10+(str.charAt(j)-‘0‘);
 95                 }
 96                 i = j-1;
 97                 while (!charStack.empty() && charStack.peek()>=97){
 98                     dp[charStack.peek()-71] = dp[charStack.pop()-71]+res*bs;
 99 
100                 }
101                 if(!charStack.empty() && charStack.peek()<=90){
102                     dp[charStack.peek()-65] = dp[charStack.pop()-65]+res*bs;
103                 }
104             }else if(c==‘(‘){
105                 int index = str.lastIndexOf(")");
106                 int newbs=bs;
107                 int curdigit=0;
108                 int j = index+1;
109                 for(;j<str.length() && Character.isDigit(str.charAt(j));j++){
110                     curdigit = curdigit*10+(str.charAt(j)-‘0‘);
111                 }
112                 newbs = curdigit==0?bs:curdigit*bs;
113                 fun1(dp,newbs,str.substring(i+1,index));
114                 i = j-1;
115             }
116             else{
117                 charStack.push(c);
118             }
119         }
120         while(!charStack.empty()){
121             char c = charStack.pop();
122             int index = 0;
123             if(c>=97){
124                 index = c-71;
125             }else{
126                 index = c-65;
127             }
128             dp[index] = dp[index]+bs;
129         }
130     }
131 }