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| class Solution {
public:
struct morpheme
{
long digital;
char operatorcharacter;
int type;
int priority = -1;
morpheme(int t, int d, char o,int p)
{
type = t;
digital = d;
operatorcharacter = o;
priority = p;
}
morpheme()
{
}
};
struct SyntaxTreeNode
{
int index;
SyntaxTreeNode * parent;
SyntaxTreeNode * left;
SyntaxTreeNode * right;
SyntaxTreeNode(int idx)
{
index = idx;
}
};
void scanning(const string str, vector<morpheme>& v)
{
char morphemetype[6] = { ')','+','-','*','/','(' };
int morphemetypelength = 6;
long digit = 0;
int len = str.length();
for (int i = 0; i < len; i++)
{
char c = str[i];
if (c == ' ')
{
continue;
}
bool flag = false;
for (int j = 0; j < morphemetypelength; j++)
{
if (c == morphemetype[j])
{
v.push_back(morpheme(j, 0, c,j));
flag = true;
}
}
if (flag == false)
{
digit = digit * 10 + (int)c - 0x30;
if (i == len - 1 || (str[i + 1] < '0' || str[i + 1] > '9'))
{
v.push_back(morpheme(-1, digit, '\0',-1));
digit = 0;
}
}
}
}
SyntaxTreeNode* syntaxtree(vector<morpheme>& v)
{
SyntaxTreeNode* root = new SyntaxTreeNode(-1);
SyntaxTreeNode* pre = NULL;
pre = root;
for (int i = 0; i < v.size(); i++)
{
SyntaxTreeNode* node = new SyntaxTreeNode(i);
int priority = v[i].priority;
if (priority == -1)
{
pre->right = node;
node->parent = pre;
continue;
}
SyntaxTreeNode* smallnode = pre;
while (smallnode->index != -1)
{
if (v[smallnode->index].priority == 5)
{
break;
}
if (v[smallnode->index].priority >= priority)
{
smallnode = smallnode->parent;
}
else
{
break;
}
}
node->left = smallnode->right;
smallnode->right = node;
node->parent = smallnode;
if (v[node->index].priority == 0 && smallnode->index != -1 && v[smallnode->index].priority == 5)
{
pre = smallnode->parent;
}
else
{
pre = node;
}
}
return root;
}
int order(SyntaxTreeNode* node, vector<morpheme>& v)
{
int value;
int priority = v[node->index].priority;
if (priority == -1)
{
value = v[node->index].digital;
}
else if (priority == 0)
{
value = order(node->left, v);
}
else if (priority == 1)
{
value = order(node->left, v) + order(node->right, v);
}
else if (priority == 2)
{
value = order(node->left, v) - order(node->right, v);
}
else if (priority == 3)
{
value = order(node->left, v) * order(node->right, v);
}
else if (priority == 4)
{
value = order(node->left, v) / order(node->right, v);
}
else if (priority == 5)
{
value = order(node->right, v);
}
return value;
}
int calculate(string s) {
vector<morpheme> v;
scanning(s,v);
SyntaxTreeNode* tree = syntaxtree(v);
int result = order(tree->right,v);
return result;
}
};
|