变量简洁正确完整思路 dfs,全局ok判断 fori作为第二个开头,forj作为第二个结尾,计算后从k=j+1开始找, <add就继续找,=add dfs,>addreturn,以下是未处理溢出的初步代码,防止前置0用了很多continue class Solution { public: bool ok=false; bool isAdditiveNumber(string num) { int n=num.size(); for(int i=1;i<n;i++){ if(i-1>0&&num[0]==‘0‘)continue; int num1=stoi(num.substr(0,i)); for(int j=i;j<n;j++){ if(j>i&&num[i]==‘0‘)continue; int num2=stoi(num.substr(i,j-i+1)); //cout<<num1<<‘ ‘<<num2<<endl; for(int k=j+1;k<n;k++){ if(k>j+1&&num[j+1]==‘0‘)continue; int num3=stoi(num.substr(j+1,k-j)); //cout<<num1<<‘ ‘<<num2<<‘ ‘<<num3<<endl; if(num1+num2==num3){ dfs(num2,num3,k,num); }else if(num1+num2<num3)break; } } } return ok; } void dfs(int num1,int num2,int end,string num){ if(end==num.size()-1){ ok=true; return; } if(ok)return; for(int i=end+1;i<num.size();i++){ if(i>end+1&&num[end+1]==‘0‘)continue; int num3=stoi(num.substr(end+1,i-end)); //cout<<num1<<‘ ‘<<num2<<‘ ‘<<num3<<‘ ‘<<end<<endl; if(num1+num2==num3){ dfs(num2,num3,i,num); }else if(num1+num2<num3)break; } } }; 处理溢出方法:数字用字符串表示,定义比较字符串大小的函数 class Solution { public: bool ok=false; bool isAdditiveNumber(string num) { int n=num.size(); for(int i=1;i<n;i++){ if(i-1>0&&num[0]==‘0‘)continue; string num1=num.substr(0,i); //int num1=stoi(num.substr(0,i)); for(int j=i;j<n;j++){ if(j>i&&num[i]==‘0‘)continue; string num2=num.substr(i,j-i+1); //int num2=stoi(num.substr(i,j-i+1)); //cout<<num1<<‘ ‘<<num2<<endl; for(int k=j+1;k<n;k++){ if(k>j+1&&num[j+1]==‘0‘)continue; string num3=num.substr(j+1,k-j); //int num3=stoi(num.substr(j+1,k-j)); //cout<<num1<<‘ ‘<<num2<<‘ ‘<<num3<<endl; string tmp=addString(num1,num2); if(tmp==num3){ dfs(num2,num3,k,num); }else if(tmp<num3)break; } } } return ok; } void dfs(string num1,string num2,int end,string num){ if(end==num.size()-1){ ok=true; return; } if(ok)return; for(int i=end+1;i<num.size();i++){ if(i>end+1&&num[end+1]==‘0‘)continue; string num3=num.substr(end+1,i-end); //int num3=stoi(num.substr(end+1,i-end)); //cout<<num1<<‘ ‘<<num2<<‘ ‘<<num3<<‘ ‘<<end<<endl; string tmp=addString(num1,num2); if(tmp==num3){ dfs(num2,num3,i,num); }else if(tmp<num3)break; } } string addString(string num1,string num2){ int i=num1.size()-1,j=num2.size()-1,add=0; string ans; while(i>=0||j>=0||add>0){ int a=i>=0?num1[i]-‘0‘:0; int b=j>=0?num2[j]-‘0‘:0; int tmp=a+b+add; ans.push_back(tmp%10+‘0‘); add=tmp/10; i--,j--; } reverse(ans.begin(),ans.end()); return ans; } };