add

Author: Hawstein

9.5

@@ -2,6 +2,7 @@
 using namespace std;
 
 int search(string s[], int low, int high, string x){
+    if(x == "") return -1;
     while(low <= high){
         int mid = (low+high)>>1;
         int t = mid;
@@ -10,7 +11,7 @@ int search(string s[], int low, int high, string x){
         else{
             if(s[t] == x) return t;
             else if(s[t] < x) low = t + 1;
-            else high = t - 1;
+            else high = mid - 1; //or t-1, (mid, t)为空字符串
         }
     }
     return -1;

9.5.cpp

@@ -4,24 +4,24 @@
 using namespace std;
 
 const int maxn = 100;
-struct point{
+struct person{
     int h, w;
 };
-point p[maxn];
+person p[maxn];
 int d[maxn];
 
-bool cmp(point p1, point p2){
+bool cmp(person p1, person p2){
     if(p1.h == p2.h) return p1.w < p2.w;
     else return p1.h < p2.h;
 }
-int lis(point p[], int n){
+int lis(person p[], int n){
     int k = 1;
     d[0] = p[0].w;
     for(int i=1; i<n; ++i){
         if(p[i].w >= d[k-1]) d[k++] = p[i].w;
         else{
             int j;
-            for(j=k-1; j>=0 && d[j]>p[i].w; --j);
+            for(j=k-1; j>=0 && d[j]>p[i].w; --j);//用二分可将复杂度降到O(nlogn)
             d[j+1] = p[i].w;
         }
     }