差分算法实现

模板

//差分一般用于
// 将区间[l,r]里面的数全部+c
//p为差分数组

for(int i=1;i<=num;i++)
{
    cin>>z[i];
    p[i]=z[i]-z[i-1];
}

// [l,r]之间的每个数加上 c

	p[l]+=c;
	p[r+1]-=c;

// 还原数组
for(int i=1;i<=num;i++)
{
    z[i]=p[i]+z[i-1];
}

例题

#include<iostream>
#define int long long
using namespace std;
int a[5000005];
int b[5000005];
signed main()
{
	int m, n;
	cin >> m >> n;
	for (int i = 1; i <= m; i++)
	{
		cin >> a[i];
		b[i] = a[i] - a[i - 1];
	}
	int minn = 200;
	int l, r, z;
	for (int i = 1; i <= n; i++)
	{
		cin >> l >> r >> z;
		b[l] += z;
		b[r + 1] -= z;
	}
	for (int i = 1; i <= m; i++)
	{
		a[i] = b[i] + a[i - 1];
		minn = min(minn, a[i]);
	}
	cout << minn;
	return 0;
}

nn = min(minn, a[i]);
}
cout << minn;
return 0;
}