给出一个有效的算法来确定在整数A1<A2<A3<...<AN的数组中是否存在整数i使得Ai=i

数据结构与算法分析——c语言描述 练习2.11

二分搜索改一下就行，只不过判断的是数列的下标。

</pre><pre name="code" class="cpp">#include<stdio.h>#define MAXN 1000int a[MAXN];bool binarySearch(int low, int high) {while (low <=high) {int mid = (low + high) / 2;if (a[mid] > mid+1)high = mid - 1;else if (a[mid] < mid+1)low = mid + 1;else return true;}return false;}int main() {int n;scanf("%d", &n);for (int i = 0; i < n; i++)scanf("%d", &a[i]);if (binarySearch(0, n - 1))printf("yes\n");elseprintf("no\n");}