#10 TLE 了

语言：C ||

#include<bits/stdc++.h>
#define int long long
using namespace std;
const int SIZE = 1e6;
const int INF = 0x3f3f3f3f3f3f;
int n, a[SIZE+1], m;
inline int read(){
	register int x = 0, f = 1;
	register char ch = getchar();
	while(!isdigit(ch)){
		if(ch == '-'){
			f = -1;
		}
		ch = getchar();
	}
	while(isdigit(ch)){
		x = x * 10 + ch - '0';
		ch = getchar();
	}
	return x*f;
}
signed main(){
	n = read(), m = read();
	for(register int i = 1; i <= n; i++){
		a[i] = read();
	}
	while(m--){
		int op = read(), l = read(), r = read();
		if(op == 1){
			int x = read();
			for(register int i = l; i <= r; i++){
				a[i] = x;
			}
		}else if(op == 2){
			int x = read();
			for(register int i = l; i <= r; i++){
				a[i] += x;
			}
		}else{
			int ans = -INF;
			for(register int i = l; i <= r; i++){
				ans = max(ans, a[i]);
			}
			printf("%lld\n", ans);
		}
	}
	return 0;
}