{"problem":{"name":"Make it Palindrome","description":{"content":"For a sequence $X$, let $f(X) =$ (the minimum number of elements one must modify to make $X$ a palindrome). Given a sequence $A$ of length $N$, find the sum of $f(X)$ over all **contiguous** subarrays","description_type":"Markdown"},"platform":"AtCoder","limit":{"time_limit":2000,"memory_limit":262144},"difficulty":"None","is_remote":true,"is_sync":true,"sync_url":null,"sign":"abc290_e"},"statements":[{"statement_type":"Markdown","content":"For a sequence $X$, let $f(X) =$ (the minimum number of elements one must modify to make $X$ a palindrome).\nGiven a sequence $A$ of length $N$, find the sum of $f(X)$ over all **contiguous** subarrays of $A$.\nHere, a sequence $X$ of length $m$ is said to be a palindrome if and only if the $i$\\-th and the $(m+1-i)$\\-th elements of $X$ are equal for all $1 \\le i \\le m$.\n\n## Constraints\n\n*   All values in the input are integers.\n*   $1 \\le N \\le 2 \\times 10^5$\n*   $1 \\le A_i \\le N$\n\n## Input\n\nThe input is given from Standard Input in the following format:\n\n$N$\n$A_1$ $A_2$ $\\dots$ $A_N$\n\n[samples]","is_translate":false,"language":"English"}],"meta":{"iden":"abc290_e","tags":[],"sample_group":[["5\n5 2 1 2 2","9\n\n*   $f(5) = 0$\n*   $f(2) = 0$\n*   $f(1) = 0$\n*   $f(2) = 0$\n*   $f(2) = 0$\n*   $f(5,2) = 1$\n*   $f(2,1) = 1$\n*   $f(1,2) = 1$\n*   $f(2,2) = 0$\n*   $f(5,2,1) = 1$\n*   $f(2,1,2) = 0$\n*   $f(1,2,2) = 1$\n*   $f(5,2,1,2) = 2$\n*   $f(2,1,2,2) = 1$\n*   $f(5,2,1,2,2) = 1$\n\nTherefore, the sought answer is $9$."]],"created_at":"2026-03-03 11:01:14"}}