常用代码片段(持续更新)
折半查找
cs
void SearchBinary(int A[];int x){
int low = 0, high = n-1, mid;
while(low<=high){
mid = (low+high)/2;
if(A[mid]==x) break;
else if(A[mid] < x) low = mid + 1;
else high = mid - 1;
}
顺序表逆置
cs
void Reverse(SqList &L){
for(int i=0;i<L.length/2;i++){
temp = L.data[i];
L.data[i] = L.data[length-i-1];
L.data[length-i-1] = temp;
}
}
快速排序
cs
int huafen(int A[]; int L; int R)
int mid = A[L];
while(L<R){
while(L<=R&&A[R]>=mid) R--;
A[L] = A[R];
while(L<=R&&A[L]<=mid) L++:
A[R] = A[L];
}
A[L] = mid;
retutn L;
}
void Qsort(int A[], int L, int R){
if(L>=R) return;
int M = huafen(A, L, R);
Qsort(A, M+1, R); //右半部分快排
Qsort(A, L, M-1); //左半部分快排
}
快速排序的划分思想
cs
//使用划分函数找到数组中第k小的元素
int huafen(int A[]; int L; int R)
int mid = A[L];
while(L<R){
while(L<=R&&A[R]>=mid) R--;
A[L] = A[R];
while(L<=R&&A[L]<=mid) L++:
A[R] = A[L];
}
A[L] = mid;
retutn L;
}
int func(int A[], int n, int k){
int L = 0, R = n-1, M = 0;
while(1){
M = huafen(A ,R ,L);
if(M == k-1) break;
else if(M > k-1) R = M-1;
else if(M < k-1) L = m+1;
}
return A[k-1];
}