#include <bits/stdc++.h>
#define int long long
using namespace std;
int n,m,w,a[100005],ans = -1,maxx=-1,minn = INT_MAX;
int d[100005];
void dif(){for (int i = 1;i <= n;i++) d[i] = a[i]-a[i-1];}
bool check(int x){
	int cost = 0,cur = 0;
	for (int i = 1;i <= n;i++){
		cur += d[i];
		if (cur<x){
			int c = x-cur;
			cost += c;
			d[i] += c;
			if (i+w<=n) d[i+w] -= c;
			cur += c;
		}
	}
	return cost <= m;
}
void solve(){/////////////////////
	int l = minn,r = maxx+m,mid;
	while (l<=r){
		mid=(l+r)/2;
		if (!check(mid)) r=mid-1;
		else l=mid+1,ans=max(ans,mid);
		dif();
	}
}
signed main(){
	int n,m,w;
	cin >> n >> m>> w;
	for (int i = 1;i <= n;i++){
		cin >> a[i];
		maxx = max(maxx,a[i]);
		minn = min(minn,a[i]);
	}
	dif();solve();//////////////////////
	cout << ans;
	return 0;
}

#include <bits/stdc++.h>
#define int long long
using namespace std;
int n,m,w,a[100005],ans = -1,maxx=-1,minn = INT_MAX;
int d[100005];
void dif(){for (int i = 1;i <= n;i++) d[i] = a[i]-a[i-1];}
bool check(int x){
	int cost = 0,cur = 0;
	for (int i = 1;i <= n;i++){
		cur += d[i];
		if (cur<x){
			int c = x-cur;
			cost += c;
			d[i] += c;
			if (i+w<=n) d[i+w] -= c;
			cur += c;
		}
	}
	return cost <= m;
}
void solve(){
	int l = minn,r = maxx+m,mid;
	while (l<=r){
		mid=(l+r)/2;
		if (!check(mid)) r=mid-1;
		else l=mid+1,ans=max(ans,mid);
		dif();
	}
}
signed main(){
	int n,m,w;
	cin >> n >> m>> w;
	for (int i = 1;i <= n;i++){
		cin >> a[i];
		maxx = max(maxx,a[i]);
		minn = min(minn,a[i]);
	}
	dif();///////////////////////////////
  	int l = minn,r = maxx+m,mid;
	while (l<=r){
		mid=(l+r)/2;
		if (!check(mid)) r=mid-1;
		else l=mid+1,ans=max(ans,mid);
		dif();
	}
	cout << ans;
	return 0;
}

当数据

IN：
2 5 1 5 8

OUT1：
8
OUT2：
13

为什么两段代码，一个调用函数，一个直接操作，输出反而不同？