haha

Author: Jie Feng

codeforces/437B

@@ -1,3 +1,6 @@
+/* Facebook
+ * http://www.mitbbs.com/article_t/JobHunting/32705761.html
+ */
 #include<iostream>
 
 using namespace std;

codeforces/437B.o

@@ -0,0 +1,51 @@
+/*
+ * http://www.mitbbs.com/article_t/JobHunting/32708791.html
+ */
+#include<iostream>
+#include<cstring>
+#include<vector>
+using namespace std;
+
+
+
+int merge(int A[], int L, int M, int R){
+    int *B = new int[R-L+1];
+    int L1 = L, L2 = M+1, i = 0;
+    int cnt = 0;
+    while(L1 <= M && L2 <= R){
+        if (A[L1] <= A[L2]){
+            B[i++] = A[L1++];
+            cnt += L2-(M+1);
+        }else
+            B[i++] = A[L2++];
+    }
+
+    if (L1 <= M){
+        cnt += (M+1-L1) * (R-M);
+        while(L1 <= M){
+            B[i++] = A[L1++];
+        }
+    }else{
+        while(L2 <= R){
+            B[i++] = A[L2++];
+        }
+    }
+
+    memcpy(A+L, B, sizeof(int)*(R-L+1));
+    return cnt;
+}
+
+int count(int A[], int L, int R){
+    if (L == R) return 0;
+    int M = (L + R) / 2;
+    int cnt = count(A, L, M) + count(A, M+1, R);
+//    cout << L << ' ' << R << ' ' << cnt << endl;
+    cnt += merge(A, L, M, R);
+    return cnt;
+}
+
+int main(){
+    int A[] = {5,4,3,2,1};
+    int n = sizeof(A)/4;
+    cout << count(A, 0, n-1) << endl;
+}

codeforces/438C

@@ -0,0 +1,70 @@
+/*
+ * given 一个字符串，这个字符串是一个算式，包含加减乘除，没有括号，符号和数
+字之间以一个空格格开，比如：“1 + 2 * 4 / 5”，return算式的结果
+ */
+#include<iostream>
+#include<string>
+#include<stack>
+#include<sstream>
+using namespace std;
+
+int expression(string exp){
+    stringstream ss(exp);
+    char c, op;
+
+    stack<int> nums;
+    stack<char> ops;
+
+    int num, num1;
+
+    while(true){
+//        cout << "New round ....." << endl;
+        while(!ss.eof() && ss.peek() == ' '){
+//            cout << ss.peek() << " ";
+            ss.get(c);
+//            cout << (int)c << endl;
+        }
+
+        if (ss.eof()) break;
+        c = ss.peek();
+
+        if ('0' <= c && c <= '9'){
+            ss >> num;
+            if (!ops.empty()){ 
+                op = ops.top();
+                if (op == '*' || op == '/'){
+                    ops.pop();
+                    num1 = nums.top(); nums.pop();
+                    if (op == '*'){
+                        num = num1 * num;
+                    }else{
+                        num = num1 / num;
+                    }
+                }
+            } 
+            nums.push(num);
+        }else{
+            ss >> op;
+            ops.push(c);
+        }
+    }
+    while(!ops.empty()){
+        num = nums.top(); nums.pop();
+        num1 = nums.top(); nums.pop();
+        op = ops.top(); ops.pop();
+        if (op == '+'){
+            nums.push(num1+num);
+        }else{
+            nums.push(num1-num);
+        }
+    }
+    return nums.top();
+
+
+}
+
+
+int main(){
+    cout << expression("1 + 2 * 4 * 5") << endl;
+}
+

codeforces/438C.o

@@ -0,0 +1,34 @@
+#include<cstring>
+#include<vector>
+using namespace std;
+class Solution {
+public:
+    char *strStr(char *haystack, char *needle) {
+        if(*needle == 0){
+            return haystack;
+        }
+        int m = 0;
+        while(needle[m] != 0) m++;
+        vector<int> preLen(m+1);
+        preLen[0] = -1;
+        
+        for (int L = 0; L < m; L++){
+            int l = L;
+            while(preLen[l] != -1 && needle[preLen[l]] != needle[L]) l = preLen[l];
+            preLen[L+1] = preLen[l]+1;
+        }
+        
+        int matchLen = 0;
+        for (int i = 0; *(haystack+i) != 0; i++){
+            while(matchLen != -1 && haystack[i] != needle[matchLen]){
+                matchLen = preLen[matchLen];
+            }          
+            matchLen++;
+            if (matchLen == m) return haystack+i-matchLen+1;
+        }
+        return NULL;
+    }
+};
+
+
+

codeforces/temp.o

@@ -1,4 +1,4 @@
-target= convert-BST-to-doublelinkedlist
+target= expression
 
 all:
 	#g++ -o $(target) -g $(target).cpp -w