add python算法模版

problems/算法模板.md

@@ -803,6 +803,46 @@ Java：
 
 
 Python：
+## 二分查找法 
+```python 
+def binarysearch(nums, target):
+    low = 0
+    high = len(nums) - 1
+    while (low <= high):
+        mid = (high + low)//2
+
+        if (nums[mid] < target):
+            low = mid + 1
+            
+        if (nums[mid] > target):
+            high = mid - 1
+            
+        if (nums[mid] == target):
+            return mid
+
+    return -1
+```
+
+## KMP
+
+```python 
+def kmp(self, a, s):
+    # a: length of the array
+    # s: string 
+    
+    next = [0]*a
+    j = 0    
+    next[0] = 0
+ 
+    for i in range(1, len(s)):
+        while j > 0 and s[j] != s[i]:
+            j = next[j - 1]
+            
+        if s[j] == s[i]:
+            j += 1
+        next[i] = j
+    return next 
+```
 
 
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