112 – Tree Summing

交啦好幾次運行錯誤，原來是數組開小了，快哭死了，本體沒別的痛點，就是建一個簡單的二叉樹，然後用遞迴取值就行了，如果學的比較好的話可以不建樹就能做 #include <iostream>#include <cstdio>#include <cstring>#include <stack>using namespace std;int N,flag; struct p{    int pri;    p *left,*right;} ;p *root;void sum(p *y,int n){    if(y!=NULL)    {        if(y->left==NULL&&y->right==NULL)        {            n+=y->pri;            if(n==N)flag=1;        }        if(y->left!=NULL)            sum(y->left,n+y->pri);        if(y->right!=NULL)            sum(y->right,n+y->pri);    }}int main(){    //freopen("a.txt","r",stdin);    int i,count1,count2,count,j,k;    char s,str[10100];    while(scanf("%d",&N)!=EOF)    {        stack<p *> v;        memset(str,0,sizeof(str));        count1=count2=count=0;        while(1)        {            scanf("%c",&s);            if(s=='(')count1++;            else if(s==')')count2++;            if(s=='('||s==')'||s=='-'||(s>='0'&&s<='9'))                str[count++]=s;            if(count1==count2&&count1!=0)break;        }        getchar();        for(i=count-1; i>=0; i--)        {            if(str[i]==')'&&str[i-1]=='(')            {                root=new p;                root->left=root->right=NULL;                root->pri=0;                root=NULL;                v.push(root);                i--;            }            else if(str[i]>='0'&&str[i]<='9')            {                j=i;                count1=count2=0;                for(i=i-1;; i--)                    if(str[i]<'0'||str[i]>'9')break;                for(k=i+1; k<=j; k++)                    count1=count1*10+str[k]-'0';                if(str[i]=='-')count1=0-count1;                else ++i;//這裡要特別注意，一定要有，即便uva的測試資料不準確，但要考慮到                root=new p;                root->pri=count1;                p *root1,*root2;                root1=v.top();                v.pop();                root2=v.top();                v.pop();                root->left=root1;                root->right=root2;                v.push(root);            }        }        flag=0;        sum(v.top(),0);        if(flag)printf("yes\n");        else printf("no\n");    }    return 0;}